My two euro-cents:
Could germany have won? No, simply because of the atomic bomb.
Could germany have won, if we assume for a moment that never had been an american atomic bomb? Although I don't believe that germany ever could/would have conquered America, I don't see how we can be sure that the Soviet Union couldn't possibly have broken down under the german onslaught. Very few countries would have managed to fight on and ultimately strike back after the enormous losses of men, materials and economic resources the Russians suffered. Few countries would have managed to completely mobilize every man, woman and child for the war effort, as the USSR under Stalin did. Had the Soviet Union broken down, with germany then occupying the country up to the Astrachan/Archangelsk line as planned, I cannot imagine how the western allies could ever have lauched a sucessfull attack on the european mainland.
About the controversy on generalship, I believe it is impoosible to rate anglo-saxian generals compared to german generals. Certainly, no western general ever achieved a victory against a superior german force, german generals did more than once. But then, after 1940, western generals never faced a superior force, so they simply couldn't prove themselves under comparable circumstances. The battle of the Bulge did prove that the army could put up a tremendous fight when locally outnumbered, but we must not forget that they had every reason to believe that they were on the winning side and had to hold out for a limited amount of time and victory would be assured. Also, the Bulge is more suited to make a point about the strength of the american infantry man than that of the american (or british) general. I don't know of any particularly inspired tactical decision by the generals in the bulge. It was the stubbornnes of the green infantry divisions that surprised the germans.
Sorry for the length of the post