Selecting just one is torture, I'd put at least 5 in each category, but here's if I don't really think too much and drop what comes to mind:
Jumps: Harlaut, Vinny
Style: B dog
Rails: Wesson and Wallisch
Wizardry: Skifi and TC
Back country huge lines: Parker White
Back country freeskiing: Candide
I'd add a street category and would put pretty much the whole Stept crew in it and some guys from 4bi9.