Nintendo games, solely cause they rarely drop in price so waiting don't help.
Basically they are the only ones I buy at full price except for a few where I want to support developer or just want the game soo bad due to it being a big like of mine.
Examples would be CDProject Red games or Elder Scrolls (not the mmo, gross)
Examples of rare occurances is buying AC4 on release date cause I love pirate things, from Pirates of Caribean to One Piece. Thus while the game will probably be $20 by February, I will still buy it cause i want it, also hopefully shows people that pirate games shoudl be made.
Otherwise as AC and other games show. THese big blockbuster games drop to $20-30 way too quick to warrent buying day 1. Why waste your money when you can get it cheap a couple months later.