I got the Rock Band PSP 3000 bundle.
The PSP 3000 is really nice. A lot of the changes are hard to appreciate if someone explains it to you. The controls all feel a lot better than on my 2000. The rounded edges make it even more comfortable to use (except when using the analog nub, which is still awkward). The screen seems a lot better than the 2000. Some people have said the scanlines aren't noticeable unless you look for them, but I noticed them right away. It isn't big deal at all and the significantly less ghosting plus better colors/contrast are worth it.
and just because it's Sony and there has to be something stupid, the system comes with with firmware 5.02 and a half charged battery. I put in Rock Band to play, but it requires 5.03...ok, stupid, but whatever. I try to update and it won't let me because the battery isn't fully charged.