I've ran XP on systems with a 450MHz PII, 128MB of RAM, and a 8GB ATA66 hard drive without a hitch other than a two or three minute boot time. As for the specs, I trimmed them up for those running in 1024x768 for whatever unknown reason. As for your love for Vista, I'm starting a pole to see how much people like Vista.
Consider this: Each game caches about 600MB worth of crap, I have 2GB of RAM, and it won't purge the cache unless it gets to like, 80%, in which case, the game crashes because the crap it just put on the RAM is suddenly GONE. That's one of MANY problems I had, I admit, the 8600M GT isn't the greatest GPU. But with vista, its about as useful as a GeForce MX series. As for Steam, I run Counter Strike: Source with it, Team Fortress 2, Half Life 2, Half Life 2 EP1 & 2, and several other games. So, yeah, lets see YOU game on it worth a crap with the system I have. Vista is bloatware, plain and simple, it eats too much of the system and is too much like a *censored* macintosh!
Vista needs to be sent to mars with all those that support it to start a new race of people who like nice looking useless software that isn't even good for the web browsers because you have to go through fifty thousand menu's just to browse the web!