Like I said, the only reason Vista uses all of that memory is because it performs very aggressive caching. It's not a resource hog. If another application needs that memory, it'll release it instantly. The reason Vista feels faster than XP in a number of cases is because it performs that caching. Microsoft isn't pushing up memory requirements because they feel like it -- they're pushing them up because there's no need to keep them down. Cheap computers come with 2GB of RAM nowadays; why not use it to make the OS run faster?
Also, vlad, if you think that Vista requiring 512MB of RAM is outlandish, try taking a fully upgraded XP SP2 system and reducing it to less than 512MB of RAM. It's probably going to run worse than a Vista system would with 512MB.
My dad had a fairly clean 256MB system running XP SP2 and it runs like ass. The only things he installed in it are Quicken, TurboTax, and Ad-Aware. He slapped an extra 256MB stick in it and all of a sudden it started running smooth. XP, when fully upgraded, needs just as much RAM as Vista does.
One thing that does make me laugh is when Apple fanboys go on about how much memory Vista takes. Guess what -- OS X requires 512MB of RAM as well.
Edit:I have 457 MB in use, and that's with all the background apps open and a firefox window eating up 88,560k. :/
Yep, Firefox definitely loves memory...
That's about the only gripe I have with it. I have to run Opera on my P2-300 (equipped with 64MB) simply because Firefox consumes more memory than the system even has. Opera's a fine browser, though, so it's all good.