Are you talking about appearance ? It's a visual style, Soft7, but I use many other ones (including mine, which is not 100% complete), following my mood and the ambient light of the room. Only program needed is the patcher.
EDIT : avoid "theme installer" or "theme pack" or "whatever they call it" programs, they mess up the system deeply. When you tweak your OS, do it manually, it's sometimes harder but you have total control on what's happening.
---
@unreal : I don't like the StartScreen and ModernUI, including this stupid difference between "metro apps" and "desktop apps", I don't like compatibility issues with different softwares/games, and I don't like other several things. But, most important, my Windows7 works like a charm, it's perfect for me, and it's still supported, so why I would pay a new OS which is not mature enough ? That's my choice and my opinion, period.