when I use it, I usually have Gpodder, Panucci, official media app, one/two/three web page opened, then some conversations may happen, phone...etc I may check some widget infos from time to time as well

but then, when this is becoming too much for the N900 (I mean slowing down), I start closing apps
I definitely love the approach: you decide what you open, what you close, finding the right balance yourself.