Your hardware is good enough to handle most everything and pretty much all Linux based distros now enable up to 64G of RAM on installation. However if you want to play games build on the windows libraries you are best off running them in a windows OS.

However the new news is that steam is currently testing a Linux client in ubuntu and will be releasing several games for Linux, some are reporting increased framrates and better performance. With that in mind, I recommend setting your computer as a dual boot, windows for windows games and ubuntu for linux based games and to consume the new linux based games.

As mfillpot said, dual booting would be a definite plus. Especially if you're into Steam games. 2013 is going to an interesting year for Gamers and Linux. You can keep up with the progress here:

http://steamcommunity.com/app/221410

I've also heard that besides Ubuntu, Fuduntu (The distro with the really strange name - It was originally a fork of Fedora with an Ubuntu sounding name.) also has the beta in it's repos. Now, if only someone had a Steam account.