given your profile here :
No, don't waste your time on the GRE, yours is already decent enough, and your research experience also, i think
I'm in the same boat here, and i'm most probably applying again next year (maybe after the last shot with the UIUC appeal )
the advice i got from a Berkeley professor, which i think applies to you as well, is to get a research intern at the US. yes, we *may* look good, full of potential on paper, but it seems guys there - in top schools - don't afford to be wrong and take their safe chances with people with recommenders they know / trust, it seems an intern at a distinguished place in US/Europe is the way to go for this . I don't know the specific effects of economy things this year, but it looks this year also was somewhat different (i.e. more competitive than previous ones).
the worst thing i felt this year is in most places i applied people didn't even take time to look at my papers,projects,..etc on my website, though my applications are filled with links to it, i received no visits at all (except, and i don't know why, from Berkeley), which strengthens my previous idea, i was rejected in the simple filtering round, not after *deepened* examining and consideration (i.e. didn't reach the *really* reading applications round)
it was shocking this year, but let's learn some lessons