I'll give you a top three.
1. PS3, because you can play PS3, PS2, and PS1 classics.
2. Xbox 360, because it's like the PS3
3. PSP, because its graphics are as good as, if not better than, the PS2.
I am a hardcore gamer so right now I basically hate Nintendo, so don't expect anything from them to be on a list of mine.
Also I'm not a Sony fanboy, I just like their current systems better. I liked the Xbox better than the PS2.