Apple :: What Is The Normal Temperature For A MacBook Running

I bought the unibody MacBook some weeks ago, probably nearing a month now. And I'd like to perhaps get some answers on some things that have been bothering me a little here and there. I've called AppleCare but they almost always tell me to bring my MacBook down somewhere to have a look at it, and that is not a very viable option. Unless it of course is something major.

1. What is the normal temperature for a MacBook running say Firefox with maybe 5+ tabs open and a video streaming in one of those tabs? Along with maybe aMSN and Pages. Before I had SMCFancontrol running, with power attached it would run at or between 55~61 degrees celsius or so. Currently with SMCFancontrol running, it runs at about 45~51 celsius but the fans are working doubly hard.

While running games on my Win XP partition, it gets hot, sometimes if I put it on my lap for a second or two, it almost feels like the surface could scald me. But I guess that's because I'm running games.

2. Is it more advisable to have the battery out or in if when I'm at home and using just the power adapter?

Applecare has advised that I leave it in all the time, but I'm not entirely convinced on this. Macs aren't PCs but most if not all of the people I know that use PCs have the battery out all the time and only plug it back in when they need it.............