"Microsoft’s long-held dominance over the computing sector is coming to an end, say market experts Gartner."
This is great news for Software and great news for people who enjoy Choice and Freedom. I'm sorry about the delay in Part 2 of the Linux Diet, perhaps I will simply post a batch of helpful tips instead. Until then I'm sure by now you have found most things yourself. You can enjoy Steam and the Software Center.
Also be sure to try DJL for more Games, mostly Free. Also the Linux Game Database has huge lists of Games for Linux. Some Games require Hardware Acceleration and need the Drivers, so make sure to check "Additional Drivers" in the Settings Menu to install those for your card; Nvidia and AMD/ATI work best for most Games.
You can also leave a comment for a Question and I will try to answer it for you if I can, or at least point you to a place that can, Ask Ubuntu is a good place to start. Hope this pretty much covers everything for now.