I'm not wondering how many apps are in the device. I'm wondering how much is running simultaneously.
When I go into /applications/manage applications and sort by size I most often see the browser at the top, then Astro then Google Maps, Mail, Market, Voice Search then Touch Input.
The relative sizes in there never seem to have much effect on the device, no matter what I'm doing with it; no lag or inadvertent rebooting, etc.
But if I leave a game for another game, then use the browser and a message comes in and I respond to it for a while then make a call then go to a video then go back to one of the games, I'll see a small amount of a slowdown if I have an email to write or whatever.
But not much. That's why I keep wondering, and am amazed every time, when I see posts in here about reboots, long lag, slow downs and freezes with the Eris. I just do not see that behavior on mine, so, as I mentioned in my first post in this thread, it makes me wonder how much is running on the Eris you're using because I cannot think of anything else that would cause a reboot other than a defective device.
But I see you may have resolved the issue with a setting, so.. cool.