I believe that the Windows 7 beta is being taken down Saturday, so please make sure to download it and try it out!
It should run fine on low-end PCs like netbooks. I've heard of some people running it successfully with 512MB ram, though that's lower than the official beta requirements, and I've not personally run it on machines with less than 1G.
I guess I should caveat my 'strictly better' speech by noting that the beta comes with an older build of IE8, which could use some polish and speed.
Also, we've discovered an early adopter of the ribbon. TurboIRC!
Very exciting to see things popping up so soon!