I have Win7, i clean installed to a different hard drive on my home rig. Which is about 3 - 4 ish years old. Its only a 3.4GHz HT with 2GB RAM and a (now) 250GB SATA HDD. I like it so far, no problems or incompatibilities other than my G15 keyboard software, which, even though it told me it wasnt for my copy of windows, installed fine when i told Windows it was intended for XP. I imagine most incompatible software will work in this manner, tho im not sure about all. The promise deal really is an issue, but it will most likely be added later on, i cant imagine its a permanent thing. That post was most immature.
Bruceb, i'm sure Win7 would work just fine on your system.