What cosmology do you use for your campaign? I personally use a system that determines a plane's nature based on it's relative proximity to the energy and elemental planes... (ie a plane that is near the water and positive energy plane will be cold yet teeming with life.
I use the Great Wheel cosmology, as it's the one I "grew up" on and with which I am most familiar. I was displeased by the lack of the quasi-elemental planes in the 3e MoP, so I added those back in. After all, who wouldn't want to Plane Shift their enemy to the Quasi-Elemental Plane of Vacuum?
-Tiberius
[EDIT: Assuming said enemy is a living creature, of course.]