Graf said:
It also applies if you're just doing the hide->sneak attack (which I would humbly submit is more common than invisibilty).
Well, there are two things to consider there.
First is the debate as to whether hiding denies an opponent his Dex bonus. It's not explicitly stated in the core rules. (Even less clear is whether a hiding attacker get the +2 bonus on attack rolls due to an invisible attacker.)
Secondly, remember that you generally require cover or concealment in order to hide, and if your opponent has concealment also, you can't sneak attack him. So while you can hide because it's dark or foggy, you can't make use of that to sneak attack. It cuts down to opportunities for hiding and sneak attacking.
In my own experience, sneak attacks come most commonly from:
a/ flanking,
b/ flat-footed opponents at start of combat,
c/ invisible or blinking rogues,
in that order. Hiding comes somewhere after that. That is, of course, potentially highly dependent on campaign style, DM, etc.
-Hyp.