Flash photo: Exposure Question

When you meter and expose your scene, do you get exposure spot on for the ambient or do you underexpose by 1 or 2 stops? I'm playing around more with my 580ex and Bounce, and before I venture into slave flash territory I want to be able to nail bounce and direct flash techniques.

Depends on what I'm trying to achieve. If the flash is just for fill, it's direct and a small part of the ambient:flash ratio. If it's primary/only light source, sometimes I ignore the meter altogether, and other times I'll drag the shutter if the ambient is worth bringing into the mix.

Check this out:

http://www.planetneil.​com/faq/flash-techniques.html

THANK YOU! That site is filled with loads of help.