Well if Bully comes back on sale I definitely recommend everyone picks it up. Of all the old Rockstar titles its the one with the best PC port. The rendering engine is fully updated to modern standards (global dynamic soft shadows, self shadowing, depth of field, normal maps, msaa support, per-pixel lighting, lots of nice additions) and it has 100% plug and play support for the 360 controller with icons and everything. Looks really good at 1080p. 100x better than the terrible Manhunt 2 port.
The framerate is locked at 30fps but its no biggie for this sort of game really, means you'll get literally zero drops on even very modest hardware, so yeah this is definitely the definitive version of the game by some distance.
The character models are still low poly of course, but the new shaders and lighting engine really give scenes an awful lot more depth and the excellent image quality doesn't hurt either.