Depends on what you mean by great thinkers.
In terms of people that will be remembered as being important by intellectuals/academics who study the shifting intellectual climate:
Lawrence Lessig
Al Franken
Maureen Dowd
Antonio Negri (maybe)
Stephen Hawkings
George Soros (maybe, though he may be considered part of the last century)
Jared Diamond
Bill O'Reily (maybe, though if he is it will just be as a representative of a larger trend which doesn't really have an intellectual to be centered around)
Noam Chomsky (maybe, though he may be considered part of the last century)
Ralph Nader (maybe, but only if the Green party does a bit better next time around)
I'd be shocked if Bush is ever considered a great thinker. (Great president maybe... its nothing against him its just that presidents as a rule are not remembered as great thinkers with the possible exceptions of Carter, who isn't remembered as a president and Kennedy, whose early death perpetuated the mythology surrounding him. Also, Lincoln but I doubt Bush will live up to those standards. Really Iraq just doesn't matter as much as the Civil War did!) But if Iraq turns out well there are a few neo-con philosophers that would be remembered. If it goes badly then there are some that will be remembered as fools.
As for great technical innovators (not because they deserve it but because they will be remembered):
Bill Gates
Steve Jobs
Linus Torvald
(Come to think of it, there haven't been that many technical innovators in this century!)
In terms of pure philosophers... That's hard to say. I can't think of too many people post-Derrada that have said anything all that new or interesting.... No real philosophical revelations this century thus far.
In terms of great shapers of popular culture. Rowling's probably, though I suspect that it will be more muffled than many of us think. (Time has a way of doing that). Actually I suspect that accurate study of 21st century pop culture will be less individual based and more corporate based. So it might be more accurate to say things like Nike.