If you spend about 5 minutes with the desktop personalization and taskbar/start-menu settings, you can get Win7 to look and almost feel like XP. It's not exactly the same, but it's real close in most important respects.
Personally I like the Windows 2000 look, what Microsoft calls the "Classic Windows" look. XP's default theme is way too "Fisher Price" for me. So the first thing I did with my XP systems was brain damage them back into Win2K mode.
Then, when Win7 came along, I found I could do the same by using the Classic Start Menu, making a few tweaks, and choosing the Windows Classic theme for the desktop.
I have had people come over to where I'm working on Win7 and say "Hey, what are you doing with Windows 2000?" and I have to laugh.
The only thing I can't get to be like XP that bugs me is Windows Explorer. The Win7 (actually Vista) version sucks and I hate it I hate it I hate it. So I went and got a third-party Explorer that works just like XP's version.
I always run my machines in “classic Mode”. It is the cleanest for me and it did help keep a consistent interface between the various computers I once had.
I used to have up to 10 machines at home running cancer research using old semi-retired machines. Those are all completely gone now leaving me with just two to maintain.
One of my two is our media server running XBMC under win 7 Home Premium.
My own personal machine runs win 7 Pro on a GIGABYTE GA-990FXA-UD5 AM3+ AMD 990FX Motherboard with an AMD FX-8350 Vishera 4.0GHz Eight-Core Desktop Processor.
I find that the AMD processors give the best value for the money. I don’t play many intense games but I do a lot of video editing and compressing which requires the horsepower.
Sometime next year my current machine will become the media server after being replaced by the latest and greatest AMD processor running at a higher speed with perhaps 16 cores.
I’ve been working with main frame computers from 1967 until an early retirement back in December 2000 caused by an auto accident. During my career I also served as a PC coordinator at a major telecom company.
My computer background lead to me building PCs for myself and others. The need to keep things consistent across multiple OSs lead to me adopting the classic look.