In Vista there is nice features like cpu load balancing and memory things, in theory.
In practise they have forgotten two things, limitations. If we would have unlimited amount of memory and CPU power it would work fine, but problem is we don't have even decent amount of those (well some have, but they are rich and happy) so how it could work well?
Sure in few years it is better when computers have much faster 4 core cpus and 8GB of ram at standard, but if instead of vista that effort has been put to XP it would be ton faster.
XP SP2 made big jump for ram usage also, before that XP was usable with 256MB of ram, after that 512MB was required and with all latest patches 1GB was not going to be overhelming indeed.
With Vista we probably see similar thing and soon it is struggling to run with 2GB of ram.
Some time ago I launched two apps that together need approx 600-700MB of mem, it took 3 hours to get them shut down as 1GB run totally out and Vista used over 2GB of memory from some odd reason.
It has odd way of using ram, when it looks like 1GB is going to be bit too little, it uses much more for same app than when 1GB looks to be quite enough (amount of other apps running varies).
Also when I took memory stick out memory usage increased by 300MB one day, have been looking into this and it does that more or less frequently, maybe it was some neat feature as using memory stick as extension of ram or something like that, very annoying anyway