Me? nothing I can think of that I purchased on my own, I usually have a rule when it comes to adding a game to my collection so I don't regret at a later time. and I go by my instincts, I usually don't buy superhero based games or games that have to do with a movie that came out. My gut feeling is generally most movie or television show licensed retro games, i believe are frustrating and unfun games from the get go.
So I don't buy them even if they are cheap. also I don't buy rhythm games or most turn based RPGs. Or any Wii game because I don't like waggling the motion controls and Wii Mote for anything other then Wii Sports and it's Mii spin offs.
I don't buy educational games or puzzle games but the ones I have are inside compilations tied with other more interesting games. My tastes are
1 Sandbox Style Games
2: First Person Shooters
3: Racing Games
4: Mostly Any Sports Video Game
6: Video Games With Multiple Games included in one package
7: Most Arcade Based Games
8 Shoot em Ups
9: Beat Em Ups
10 Fighting Games
11. Easy Strategy Games
12. Third Person Shooters