Trophies wouldn't stop me from getting a game. With that said, I do enjoy a game more when the trophies present a challenge. It's really not fun if you're just getting trophies for inserting the game into your disc tray.
I loved the trophies in Demon's Souls because they forced you to explore every inch of the game and the easiest ones were actually for beating bosses.
EDIT: But then there are some that are just rediculous and off putting... Still can't believe a few of the trophies in Prototype and Confrontation.
4 ≈ One