I'm not that big a fan of the new Ubuntu scheme honestly. I'm running it on my merrybirthdaymas rig as a partition currently. Like Hex said, I play too many games to not keep Windows, the sorta necessary evil. I know wine runs a great deal of stuff but more advanced games still bog it down too much. I plan to get a SSD to run games in Win7 and then my main hard drive will get a full install of either Mint or Ubuntu and my windows drive will never see the internet again. I may try a few other versions out before settling though.
I built a new box a couple of weeks ago with an 128GB SSD for the OS/current games/apps and a 2 TB HDD for storage, and it is LIGHTNING fast. My load times in ME3 are literally a couple of seconds, so fast I cannot read the tool tips. Go for it!
Why will the windows drive never see the internet again? Won't that be a problem for Steam/Origin services, patching, multiplayer, etc? Just a suggestion, maybe use the SSD for Win7, and partition part of the HDD for a linux system partition. Make another partition out of the rest of the HDD with NTFS and then mount it under both Windows and Linux for shared storage. WINNING!
Everybody good, plenty of slaves for my robot colony?