Shooting in poorly lit areas...

It's easier to correct underexposed images than overexposed, especially when you're shooting RAW. So if you have a choice of underexposing or overexposing, just expose it correctly

Correct an underexposed picture and you end up with more visible noise. On the other hand you'll be amazed how much can be recovered from blown of highlights with the Shadow / Highlight tool in PC CS.

That's absolutely right.

I've got "Camera RAW with Photoshop CS" on my knee. If you have blown highslights it's sometimes possible to recover highlights so long as you've only blown one (or maybe two) of the three color channels. So long as you've got >0 in the 3 channels you can make something of it.

Of course this is book learning and bourbon talkin, but if I had the choice of under or over exposing, i'd choose under.