I see I'm the only one who voted for clone trooper. I assume the question means which one is the best choice visually, and I feel that the clone troopers fit the bill as the galaxy's most elite troops. Stormies do look slightly more "real" in some sense, but (especially in ANH) they're just some extras in suits and don't act (or necessarily look) like elite shock troops. I also prefer the AOTC troops for the slightly more unique look and obvious Mandalorian resemblances. I felt the ROTS troops were, ultimately, CG stormies with new visors. And colors. Ooh, pretty colors.
EDIT: And I know that the ROTS trooper are in my sig.