Picking one is difficult, of course, though I probably tend toward Manstein slightly, since he demonstrated ability in a number of settings and with varying resources.

On Patton, I agree with Kraxis. He was a hell of a leader in many ways, but had some egregious flaws. The only time he was ever used optimally was in the initial breakout from Normandy. That is, someone ELSE did the breakthrough attack (without hammering head-on straight at the strong point like Patton) and then Patton's forces were unleashed for the "broken field running" at which he may have done as well or better than anyone.

Zhukov lived up to the reputation too many people hang on Ulysses Grant. Z was tenacious and aggressive, but his tactics weren't really "inspired." With all respect for earlier comments, his Siberian success isn't quite so impressive when you factor in the negligible Japanese armor and light artillery formations. Flanking with armor when you know the other chap can't isn't quite so shocking, and Zhukov had lots of tubes compared to the Nips. Z did know when he had the bigger hammer, and wasn't afraid to use it.

Mannerheim was a good leader who knew his resources and terrain well -- always excellent qualities. A contender.

All-around, I have always had a respect for Bradley. He seemed to have the knack for getting things done -- despite the lack of flash or reputation for brilliance in any single aspect of generaling.

I'd also add Yamashita for consideration. I've always wondered what he would have done if Japan had had a tank force of note -- he certainly wasn't a slouch when it came to speed and shock warfare.