Since I rarely paid full price for new games in 2010 (Amazon sales, Steam sales, etc.) I didn't have many major regrets.
For a game that cost less than $20, it hardly matters if I only play it a few times. At $30-40, it doesn't matter if I never bother to finish the game.
But at regular retail price, if you can't wait for a sale, that should mean you want to finish the game as soon as possible and then start digging into all the extras. If not... you may as well wait until later.
So maybe the topic should be which games did you buy that you regret paying full price for.
I paid close to full price on Alan Wake, Halo Reach, Heavy Rain, Metroid Other M, God of War III and CoD Black Ops.
Of those, Metroid was definitely not worth my $50 as I have no intention of finishing the game. I loved it that much.
I didn't buy Black Ops, but I'm pretty sure the copy that was given to me was bought full price, despite my insistance that I wasn't buying the game because it wasn't worth $60 to me. Still not worth $60 even though the game is unlikely to be heavily discounted until the next CoD is released.
I could have waited on most of the others, but... I did finish Alan Wake, Heavy Rain and Halo Reach on the first weekend I had my copy, so; worth it.
I've yet to finish a God of War game (I have all of them).
