Time for some interim results:
- more than 200 votes making this at least partially statistically relevant
- over 100 posts detailing the apps or the usage behavior

- over 80% keep typically 1 to 6 applications open on the multitasking view of the Nokia N900
- over 97% of all respondents pro-actively manage the amount of open apps
- only less than 1.5% of all respondents do not close apps actively and leave them all open
- at least 35% of all people detailing their open apps keep various third-party apps open

So, this is becoming now a number play. Unlikely, that the overall result will change massively (or will it over time?) but the influence of this poll grows significantly with every vote. So, keep on making sure your input is registered.