I love the multi task function and would use it like crazy if my n900 was not as buggy as anything. I have enough trouble receiving calls without anything open - many times phone rings with blank screen, goes straight to voicemail or just flashes up missed call without ever ringing. So it would mean I do not want to be able to use the device if I leave many things open.

Without the bugginess on my device I would probably always have about five things at least, open at anytime.