I have OEM Vista Home Basic SP1 and upgraded to Ultimate SP1 and i love it. Who says it needs 2GB RAM? After my optimization it uses only 36% of the RAM shown on task manager. You only need 2GB RAM if you do gaming because that can use up to 70% RAM which is excess 50% (1GB). Rest are on pagefile.
The performance with Aero works really smooth even on the low end GMA X3100 as far i see. Anyone have dedicated card should able run it extremely well. There's no such thing as "slow down on gaming" that are just sick rumors. There might be few fps slowdowns but is not something you'll even notice.
Everyone complains Vista uses alot resources that is true because the "Early Prefetch feature" loads windows apps into the RAM so when user wants to run it the program can be launch instanly without loading all required DLLs files resulting faster access, also known as 'much more responsive'. You can see a clean install of XP uses no more then 100MB RAM but Vista takes up to 800MB. I was very concern about this but after a while i see there's no performane impact with other RAM resource hungry apps.
Hardware issues i have nothing more to say but stick with the hardwares from 2008 is the best way to aviod compatibility issue. If you own Intel CPU, Chipset and a nVidia/ATI graphic card you're prime and good to go with Vista. One thing i sticked with vista from now is the fancy GUI and the new kernel and revised file system.
@Baskir, Work best if you have 4GB RAM, the same 32bit app on 64bit tend to use more RAM. Resulting better have more RAM.