Some time ago (sometime around 10/2006) I installed Windows Vista (a release candidate at that time) on my home machine in order to "try" it (to be sincere I've installed various Vista beta/release candidates).
Performance was not impressive but since I'm a software developer (and I didn't used the machine to work anyway) I decided that it worths to be able to experiment with new API / functionality so I kept it.
Some time after that it was released so I got a copy and installed in the same machine.
On 10/2007 I joined db4o and started to work from my home which means that my machine now plays an important role in my development productivity and I decided that I'd rather go with Windows XP (x86 or 32 bits) again (due to the performance impacts I got with Vista x64).
Well, one year passed and I got a new machine (a pretty fast one, lets say) and so I decided to give Vista x64 a try again.
In the first days I do got some BSODs (which made me feel frustrated) but after spending some time searching I found some suggestions regarding memory configurations; after applying such changes (I just set the times after memory manufacturer specifications and increased memory voltage by 0,1 volts) it became stable (no BSOD since them).
I can say that I'm satisfied up to now; no hardware or software conflicts, performance is pretty good (much faster than my previous machine running Windows XP - I know, XP would run even faster on this machine).