I can't say I'm super knowledgeable about theory and history, but here's my two cents.
I'd say that some of the most influential card men are still the classics; vernon, marlo, scarne, lepaul, forte, etc. Even though they're long gone their tricks and techniques have influenced a vast majority of the card work done today.
The more recent card workers who I think are the most influential are probably Chris Kenner, Jason England, Paul Wilson, Gary Plant, Aaron Fisher, Dan&Dave, Bayme, and to an extent Daniel Madison (I only say to an extent because I expect ten years down the road he'll have become even more prominent). If ellusionist has their way, Bebel could get pretty big in the next few years as well. (although they may need to start subtitling his downloads) It also can't be ignored, of course, the amount of fledgling magicians who have found their way thanks to Brad Christian.
When performing for laymen, I prefer the classics. Acrobatic Aces, Here to There, The Biddle Trick, ACAAN, stuff like that. When I perform a trick for my magician friends I like more fooling stuff, like Never Fails by Gary Plant, LePaul's signed card to envelope, or pretty much anything from Wilson and England's Unreal Sessions. I'm a particular fan of Lance Pierce's contribution to the series.
I'd be really interested to see what magicians more knowledgeable than myself might have to say.