Considering buying World of Goo from Ubuntu Software Center, but not sure what happens after that.
All my computers use the same Ubuntu SSO account - does this mean I can install it on more than one machine for the one fee?
I would recommend buying the game on steam. If you do so you would be able to install and use it on multiple machines and/or operating systems. Though I don't know how stable the steam linux beta currently is running. It is worth a shot.