There is nothing in either Pro or Ultimate that would enhance gaming... Home Premium is more than enough. You could even stick with Home Basic if you don't care about Aero. When it comes to gaming, it really doesn't matter... it's the other features that you have to decide upon.
Another vote for HP. The XP mode found in pro+ won't do squat for gaming. Its not accelerated, so you won't be able to play games in XP mode. Pro also doesn't add anything that you can't get for free off the net. Remote desktop? Try logmein. Ability to join a domain? Doesn't help gaming and few of us use a domain at home. Bitlocker and other such equivalent things can be found online, and for free no less. Home premium is honestly all you need for gaming.
How many games use more then 4GBs of ram? How many need 16GB?
This could end up like cores and XP. When XP first came out home supported one socket and one core. Then Intel's HT came about. Still one socket, but 2 cores as far as the OS knew. You would have needed to have pro installed if you wanted to use a HT CPU.
MS changed it however. They decided to count sockets instead of cores. Home would now support one socket but as many cores as AMD or Intel could put in there. I suspect they may do the same thing if we really start bumping up against the 16GB limit. And even if they don't, by the time we start to hit that limit we'll be using win 8 or 10, etc.
And you wonder why I complain about your posts? First you imply there is an issue because your GPU ram is included in that 16GB total, then you state that 16GBs is overkill.
As I stated earlier, we'll be on a different windows by the time we care about a 16Gb ram limit. Windows 8 is coming next year? 9 perhaps 3 or so years after that? 4GB is just now coming standard, so 8 (or 12GBs if your on a tri channel board) is the next step. I'm sure we can ride that till win9, assuming MS doesn't up the limit. Again, Windows 7 HP is all you need for gaming. Anything Pro or above offers can be solved with free tools already available. No need to pay for anything extra.
Let me just ask you one Q? what kind of performace do you have like graphic wize like AMD or Intel. If you have a higher performace on your graphic cards it does not matter which verison you use Windows 7 Starter is even good for gaming let me tell you that much. If you just want something simble and easy go with Windows 7 Starter and even that you can download the pererized just go to http://www.youtube.com/watch?v=yO2-EcJ8rag Go to the discription and download it and you can get aero and it works I have it on my windows 7 starter edition aero and it looks nice.