I've recently stopped buying big-name games when they first come out, and it's working something of a treat.
I've come to the conclusion that popular multiplayer titles should be bought as soon as possible, simply because that's when they're at their busiest and there's plenty of people to play against. I don't mind forking out launch prices for titles like Call of Duty 4 or Gears of War 2, then.
For single player games, I find it completely different. I decided to skip a lot of them when they first came out, and I'm now faced with loads of games at dirt-cheap prices. Recently picked up Oblivion for £15 and it's a cracking game so far.
Being a single player game, I'm not missing out on anything by being late to the part. In fact, it has its benefits - all the patches are already out, making for a better experience.
Had a look around and I can also now get titles like Assassin's Creed, Mass Effect, GTA IV and others at around £20 each - about half the cost of buying it when it first comes out. Most of those titles have been patched, too.
Gimme six months or so and I'll be starting on Fable II.