Ok, for PS1, you can and should try most of the Final Fantasies, Spyroes, Crash Bandicoots, Twisted Metal 3 & 4. And if you EVER played Chrono Trigger (which every self-respecting video game player should at the very least know about), there is a sequel called Chrono Cross, with TONS of characters (but very few double and triple techs, sadly) and different endings.
(Assuming you like RPGs)
Grandia 1 is also not bad and will last you quite some time. Tomba 2 is also not bad.
Legend of dragoon. You MUST play this. Saga frontier 1 and 2. <.< Wild ARMS 2 <- Darn good. Legend of Mana, good but meh... Dragon Warrior 7, VERY LONG game. <.<
About it for now. :p