I have PAIN and Echochrome but they weren't really any good. So I was wondering what games people could suggest.

I can't speak from personal experience since I don't have a PS3, but I've never heard anyone complain about Flower, so you might want to check that out.

pixel junk monster: tower defense.

Flower, pixel junk moster and eden heard great things of shooter as well but haven't played it yet. Braid. I like fat princess but others don't like it as much. Super Stardust. Trine.

Fantastic games with universal appeal IMO:

Flower, Pixeljunk Monster, Pixeljunk Eden, Pixeljunk Shooter. Don't think you can go wrong with this selection

If you're looking for some specifics kinds of genres like shooter, puzzles, blah, I think these games are very much worth looking in to:

Critter Crunch (puzzle) , Shatter (Intresting take on Pong, brick destroyer), Crash Commandos (Side scrolling shooter with online still full of people!!!), and if you're going for something big, Wipout HD (It's Wipout, but in HD!!!).

Flower, my game of the year.

PixelJunk Monsters and Super Stardust HD are my top picks. Braid is also excellent. I personally like Everyday Shooter as well, and both Shatter and Flower are worth playing.

Wipeout HD + Fury for a bigger game.

Also: Critter Crunch

I highly recommend:

PixelJunk Monsters
PixelJunk Eden
PixelJunk Shooter
Flower
Super Stardust HD or Everyday Shooter
Ratchet and Clank: Quest for Booty