I'm seeing what the OP means now. Well I guess I'll make a proper list now.
Grand Theft Auto Series - You can do anything and if you die you just respawn at a hospital.
Animal Crossing Series - A simple, yet fun existence. (You're also a Mayor in the new one.)
Ed, Edd, N Eddy The Mis-Edventures - You get to hang out with all the people from the show so it would be amazing.
Scribblenauts - You have the power to get almost anything you want by typing the name of it up.
Pokemon - I don't even need to explain this.
Final Fantasy Series - The worlds those games are set in are just cool.
Psychonauts - You're a psychic soldier.
Mass Effect Series - Reapers, Geth, and Seran. (Seran was the main antagonist in ME1 right?)
Warhammer 40,000 Series - Self explanatory.
Resident Evil Series - Zombies and Zombie like enemies everywhere.
Skyrim - You have to fight dragons, trolls, guards, orcs, and a bunch of other people all the time.
Darksiders - Gods and stuff destroying mankind.
Infamous Series - You get awesome powers but then have to fight all these gangs.
XCOM Series - Aliens everywhere.
Brutal Legend - A Metalhead's dream, except there is a lot of stuff out there that wants to kill you.
L.A. Noire - Awesome location and time but all those people who would try killing you for being a good cop.
Sleeping Dogs - An undercover cop in China who joins the Triads, Cool! But you have to be a good cop and not so good Triad so juggling those two might be hard.
Hitman: Absolution - You're a deadly assassin who goes rogue, meaning you have deadly assassins chasing you down and that sucks for you.
Hotline Miami - You're a killer in the 80's? Awesome! But wait you get murdered super duper easily.
Shadow Of The Colossus - You can kill Colossi but you have to kill Colossi so yeah.