This article shows the major differences between the Windows 7 editions:
Windows 7 editions - Wikipedia, the free encyclopedia
The professional and Ultimate editions have many advantages but they aren't particularly important to a home user.
The Ultimate and Enterprise editions are essentially identical. The only real difference is that the latter is not a retail product but available only to large organizations with bulk licensing.
I don't know if this link was posted.
Compare Windows 7 - Microsoft Windows
Compare Windows 7 Editions
Home Premium to Ultimate (this is a link to my post, post #2)
:)
They are all the exact same OS with a few extra expensive features to unlock - which have better 3rd party freeware alternatives like Team Viewer, virtualizing freeware, etc.
As strollin mentioned.. for a home user or system builder who likes to max out the ram on the system, the memory limitation would be the most important consideration.
My other win 7 and 8 machines are 64 bit so I decided not to have Ultimate on 64 bit so I can't take advantage of the extra ram, but for my purposes 3.5 gb works fine. I am hedging my bets in case some legacy software cannot run on 64 bit.
The Wikipedia comparisons are very interesting, the 192 gb allowance for ultimate is generous but check out win 8 pro, you could use 512 gb. None of my pc's have more than 8 gb installed although two of my motherboards can accommodate 32 gb. I have found that adding extra ram seems to follow the law of diminishing returns most of the time.
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