What should I play? Pick 1 of 10.

Voted Blood Dragon. It's fairly short which lets you get it done and move onto the next one if your actually wanting to make progress on a backlog, plus it'll give you something of a feel for the gameplay of Far Cry 3 as well. Whilst some of the missions are partially designed for Stealth the game doesn't really support Stealth as a playstyle all that well early on. having a personal preference for stealthy gameplay I found it a bit awkward going from 3 to Blood Dragon the first time I played them.

Voted for Rayman.

Witcher 2 is a fantastic RPG. You should enjoy it :P

The Witcher 2 (but ffs, PLAY TW1 FIRST!)

I haven't played The Witcher 2 yet, but i played The Witcher 1 and loved it.
And i saw that you haven't played BioShock 1 and 2.
You could consider playing these games too :)

Rayman all the way! Absoloutely amazing game with an epic soundtrack and just all round great gameplay. More people need to play this game!

why there is no flappy bird in there?

I would play Devil May Cry 4 or Killer is Dead.