I accidently voted for PS1 but my order of merit is as follows.
1. PS2 (because its the PS2 end of story)
2. PS1 and PS3 (I have the PS1 equal to the PS3 because who can forget debut games like FFVII, Tekken, Crash Bandicoot, Abe's Oddysee, Medievel and Tomb Raider.)