Your list of top 10 games that are similar in style to Fallout 3 / New Vegas on Xbox 360

I'm looking for a list of your top 10 games, but more specific than the usual top 10 of 2011 or top 10 all time. I've recently, over the last year, transitioned from playing games like Modern Warfare and NBA 2k11 to playing games like Fallout 3 and Fallout New Vegas. I'm addicted and can't stop, but now I'm looking for some new titles to check out and they don't necessarily have to be from 2011. I recently purchased Resident Evil 4, because of the great reviews, but I lost interest in it fast as it had too much of a "follow this path" style play and not enough free roaming, open world that I fell in love with in Fallout. I was thinking about Skyrim since it's from the same maker but I'm not quiet into the whole midevil time period. So I've been considering starting into the Bio Shock series or the Dead Space series, but overall just looking for some guidance from other gamers, as I don't have enough time to play them all.

Well I hope this gives everyone an idea of what type of games I'm interested in and I'm open to any ideas. I figured asking for a top 10 list along the lines of this genre would be a good start.

Thanks for your input and replies in advance.