Use Process Explorer to see which processes is hiding in that svchost. Could very well be Superfetch is part of that bunch. Rightclick, see Services tab.
XP works ok on a 512mb machine so Vista needs double, 2gb is more than enough to "barely run". You cant compare usage on a 4gb machine with a 2gb since Vista will not act the same. What whoever put in machines is more depending on $$$ than what actually works the best. They dont care. Not really what the thread is about, more like "shocking" memory usage for no good reason and Vista not releasing ram when required - or something. But you are right that Vista is not XP
You can disable all you like btw, take out superfetch, readyboost, readyboot, indexing - every low priority process you can find. May be even force "freeing up" mem with those fantastic mem cleaners avail. Up to you. To take control over what is running is kind of freeing up memory/resources as well - makes sense too. Some with Dell type bundles (more so on weaker machines) can have lots to gain by this. This has not changed in Vista. Tweaking services, startups, using best programs, avoiding crap programs!
Believe it or not but I clearly remember many people whining about how dumb XP was, like not taking advantage of installed ram. Possible Vista is too agressive and fixed with its systemwide cache-mania, like you cant control Superfetch, but which path you think is the right one to chose?