It took me a while to finally install Vista and use it. I just go off XP with the last service pack.
I am trying Windows 7 now and it's a throw back to the early days of Vista. My Windows 7 system is exhibiting extreme instability. In particular the keyboard and mouse drivers for my Microsoft Sidewinder x6 keyboard and x5 mouse aren't functioning properly. The mouse pauses if I move it quickly. The keyboard input will sometimes repeat for no apparent reason.
Sling player will pause for no apparent reason.
Adobe Flash doesn't appear to work always.
I guess I'll be waiting for Service Pack 1 or later again.
BTW running on standard Dell's with 4Gb or RAM and i7 / Quad Core processors.
I've had very good success with Vista lately since the last service pack.