Fallout 3 is really not that great, its fun, but really not that great. It would be as boring as Oblivion was and is if it wasn't for the fact that you can make enemies explode with the proper perk. I would go with MGS 4, there are so many different ways to play that game it not even funny. The areas are large enough to allow for some exploration without you having to do a bunch of annoying leg work unlike Fallout 3. If you like shooters wait for Killzone 2 (It comes out next month.) to come out and give it a rent before you decide to buy anything at all.

Geez, everyone, THANK YOU for all the advice! I didn't expect to get this much of a response, to be honest.

I have weighed everyone's opinions and you all have helped me make my decision. Not gonna say which game I'll get - that way I don't make anyone upset - but I'm sure it'll be a good decision now.

Thanks again!

Oblivion > Fallout 3, so... Oblivion (If you don't have it, if you do, then get Fallout 3)

i say buy Wall-E. the films great and the Burn-E extra is so funny

darrinwright:
Oooh, Fallout 3 does sound good. So does World of Goo. Unfortunately, no 360, and I own a Mac, so no L4D for me.

Yeah, but at least on the mac you can use the exact same software that is available for the PC to make neat videos.

All games mentioned are their own beast, depending on what you enjoy and are looking for out of a game experience I would change my recommendation. i.e. not enough information.

Fallout 3 is the most critically acclaimed of the titles you have listed, followed by MGS4, but the two games are not really comparable.