Great info guys, really apreciate it.

Most of what was said were my "guesses" but it would sure suck to die because of a guess <img src="/images/graemlins/wink.gif" alt="" />

I think the biggest is Comfort vs. Survival rating. That right there means you shouldn't base your bag rating on the temp you will be sleeping in <img src="/images/graemlins/wink.gif" alt="" />
Also accounting for a tent which will/should be warmer inside than the airoutside too.

Thanks again!
-Todd