PS1 is still my favorite by a considerable margin but the PS3 isn't all that far behind the PS2 in my personal opinion. Second half of the PS3 was absolute awesome but the first half is really hard to overcome. The PS2 had a ton of games but many of them were subpar. It had as much trash as the Wii.
It's really pretty difficult to measure and entirely subjective.
Exactly as I feel. PS1 will not be dethroned for a while IMO. But PS2 might