Vista poses massive problems with copying DVD's and CD's especially anything with copyright.
Vista doesn't like Any DVD a very popular program for cracking copyright and can have some seriouse problems with copying programs like Disk Juggler and Nero.
Also Gamers suffer badly, that $100 favourite game that you bought last year probably won't work under Vista.
Vista is a major step for Microsoft, Sony and other large publishing companies in controlling and eliminating copying of copyright material, that includes Movies, Music and Programs.
So if any of the above relate to your computer use then Vista is not for you at the moment, but if the above does not relate to you then Vista is a good experience afterall Vista has become very Apple like, just ask an Apple user and they will confirm how good an Apple computer is.
So if Internet use, Office use ie: Word, Excel, Publisher etc. is your main use then Vista is great allthough you may have to upgrade your office package to Microsoft Office 2007.
Yes johnpony your AMD would kick butt under any operating system and would be a pleasure to use, but by the specs that you have outlined you have admitted to being a very serious gamer who demands lots of grunt, nice machine.
I personally prefer XP proffesional allthough I have a dual boot system with one hard drive running Vista Business, I do admit that I only have Vista running for the learning curve because of my customers.
Peterp