This is difficult for me. I love the first party games on the PS3 but this generation has been lacking in epic RPG titles. Normally I would say the PS2 because it had EVERYTHING, the game library was amazing. Whatever kind of game you wanted to play, you could find.
However, I'm going to vote for the original Playstation. It was the first console to ever blow me away. I had an NES and a SNES previously, but I ended up getting bored with both of them. So many platformers, so many shallow characters and games with stories that made Dr. Seuss looks like Hemingway. They were like Saturday morning cartoons but then the Playstation came along and it was like watching Vampire Hunter D late at night instead. It made me really interested in gaming, where before it was just something I did to kill time.
The PS2 might have had the biggest collection of really good games, but the PS1 had so many absolutely groundbreaking titles, so many games that I think of as masterpieces. I'm glad that little box showed up.
