I don't think you've been very accurate in your assessment of Hitler's military prowess, so i'll start by arguing the points you've mentioned.

Here we have a man who was in the position of having superior generals, superior technology, and superior troops and squanders it all because of bad decisions.
While I can agree with superior generals and mostly superior troops, it's superior technology and bad decisions that I disagree with. What defines superior technology? Yes, for example the Panther and Tiger tanks were powerful vehicles but they were all notoriously unreliable. For example, if you take the Jagdtiger and Tiger II's, despite them never having been disabled by an Allied tank from the front (the metal plating being too thick), they were prone to breaking down. If I recall correctly, of the approximately eighty Jagdtigers produced, more went out of action from mechanical breakdown rather than actual combat, and for the Tiger I when bringing up unreliability, it consisted of 26,000 separate parts.

On top of this, you have to acknowledge that the Allied blockade and bombing campaign resulted in Germany suffering material shortages later on in the war which required them to use material substitutes and to streamline their production techniques which made later vehicles of a reduced quality and despite being able to produce a greater quantity of vehicles their original mechanical issues were simply hampered by this.

Then you say that he made bad decisions. Well, it was exactly Hitler who ordered the invasion of France in 1940, and that was an astounding success. Hitler too acknowledged (although the whole "it was impossible" argument is raised, that's deflecting from the point) that in order to stand any chance of winning the war, Britain and the Soviet Union needed to be knocked out. Indeed, his execution of his attempted submission of Britain was lacking (wasting hundreds of aircraft and crews) and his occupation strategy for Operation Barbarossa didn't help at all, but he realised what he actually needed to do to win the war. It was only later on when he started to become mentally unstable that this started to fade from view and he insisted on resorting to trying to resort to unconventional methods such as constructing rockets and absurd vehicles (e.g. Maus).

Case and point: Stalingrad. Hitler messed up several times here before the battle for the city itself ever truly began. First, he devoted large amounts of manpower meant to cover the flanks of his assault on the Caucuses to the attack of a strategically unimportant city. Then, as if that wasn't enough, he strips all the armor away from the assault on Stalingrad to speed up his attack on the southern oil fields. The attack in the south finally starts to move again, but (surprise) his attack on Stalingrad now stalls out. So he turns his armor around again and sends it back up to Stalingrad leaving his assault on the Caucuses to stall out and inch forward.
I'd hardly say it was strategically unimportant. It's an industrial centre and a link between the Caucasus and Moscow fronts for Russia so severing that link would have made their position in the Caucasus quite untenable. You also criticise his insistence on protecting his flanks, but considering we're using Stalingrad as the example here, wouldn't protecting them have been logical considering what happened later on?

Skipping ahead through the entire battle of Stalingrad to the end, once the Russians have encircled the entire sixth army. The Sixth Army could have, if they moved quickly, broken out of the encirclement to live to fight another day. Instead, Hitler orders them to stay put and hold until relieved under the assurance by Goering (another candidate for worst general simply because he cost Germany many men by deluding Hitler as to the actual power of the Luftwaffe for his own personal image) that the Luftwaffe could airlift the (if I recall correctly) 700 tons of supplies that the Sixth needed daily through the Russian Airforce (which now controlled the skies mind you).
Despite him being wrong in his belief that Sixth Army could hold out, it was based on previous experience. General von Seydlitz-Kurzbach had been encircled at Demyansk during the winter of 1941-1942 and had been able to be broken out after being airlifted supplies to his encircled troops, so Hitler based his belief on that anecdote.

The army only got around 80 tons daily, a far cry from the necessary amount. So in one fell stroke Hitler had lost an entire army to the Russians. In fact, of the several hundred thousand men that surrendered at Stalingrad, only a few thousand would ever see Germany again. The rest would die in Russian POW camps (just a little aside).
Well that's just a lie. I don't have the figures on hand, but it was more than 80 tons that they received and was clearly only in the very last days of the encirclement when tonnage dropped that low. Also, one has to consider that were it not for the heroic sacrifice of Sixth Army at Stalingrad, the Germans may not have been able to recover from the disaster. Manstein was able to stabilise the front during the early months of 1943 but if Sixth Army and Operation Winter Storm hadn't been launched which sapped at the Russian strength in the area then things could have ended up a lot worse.

That is just one of Hitler's many blunders. Another would be Normandy during Operation Overlord. He refused to allow Rommel to move his Tigers to the beaches because of his fear of an allied attack at Calais (a brilliant deception on the allied part if I may add). That is understandable, I probably would have done the same in Hitler's position. However, even after the landing had started and Hitler new the scope of the allied assault, he still held out on allowing Rommel to move his tanks for fear of an attack at Calais. At this point I feel that the true allied intentions would have been fairly obvious, and those tanks could really have made a difference in the days following the attack.
It's easy to say with hindsight that you would have just sent the tanks up front, but you have to bear in mind that the German intelligence system was a complete joke. As well as that, even now I disagree with Rommel's assessment of what should have been done at Normandy. Yes he was correct in guessing that the landing would have took place there, but the Allies had complete domination of the skies and naval superiority. The German counterattacks during Operation Avalanche and Operation Husky had both shown how devastating naval gunfire can be to armoured vehicles, and during Operation Overlord if I recall correctly the Panzer Lehr division lost approximately half of its complement of tanks while it moved up to the front due to Allied air sorties. Imagine then what it would have been like for the Germans to be approaching the beach with the largest armada ever assembled right there along with an enormous airforce which could pound their men and armour in to oblivion?

The bocage was defensible terrain, along with the rivers, villages and urban areas of Normandy (Cherbourg, Carentan, Caen) so to organise a defense in-land seems like the logical decision to me. Yes, the Allied airforce will cause trouble, but at least you would be out of range of the naval guns, plus considering the terrain north of Caen and east of Bayeux was mostly clear, if you could have kept the Allies pinned there while having the protection of the bocage for your own troops that could have been far more deadly than simply rushing to the beaches.

Hitler was a man with no real military experience who took over the armies of an entire nation and blatantly ignored (or even sacked in the case of the failed assault on Moscow, an assault which failed because he order the troops to wait until it was too late) his best generals. Germany has always been a source of amazing military minds, and instead of using this tactical genius to his advantage, Hitler wasted it by taking control himself. In fact, he even micromanaged German forces in Russia down to the battalion level.
Hyperbole. Hitler didn't manage forces down to battalion level, that would just be absurd and would have made the entire command structure redundant. Also, that goes entirely against German military doctrine. The reason the Germans did so well (and suffered so many casualties when it went wrong) during World War I and World War II is because unlike the Allied and Soviet structures which relied upon completing set objectives and then requesting orders from higher command (though the Allies did rectify this later on) they relied on their junior officers to take in the situation and simply act accordingly to circumstances. Has an objective been taken early? Then perhaps an assault can be organised deeper in to the enemy's defenses. Have the enemy occupied a command post? Then it's time to strike back and take it.

Yes, Hitler did have a few strokes of genius (The Battle of the Bulge) but often they were too late, or not properly followed up on and supported. For these reasons, I feel that Hitler, though not strictly a general, is one of the worst military commanders in history.
I'd say he was a clever and rational man tainted by later insanity and his ideology. While his beliefs on race are morally wrong, to breed the strongest among a kind with the strongest of the same kind is biologically a perfectly good thing to do as it creates healthy children. It's morally where it goes wrong, as to do so Hitler wanted to exterminate other "inferior" races.