what exposure mode do you use on your XTi?

I read the manual and played with the modes, but I'm not seeing a huge difference between them with and without a flash.

What "metering" mode do usually have your XTi set on and why?

Evaluative, Partial or Center-weighted?

it all depends.

P is similar to auto, but allows for some changes and RAW shooting.
AV - when you want to control DOF first
TV - when you want to control the length of exposure
M - when you want total control

with flash, in P it will be auto settings, in av and tv it will be fill (it will do a ambient exposure based on lighting and just happen to flash also), in M you have control to set the ambient light and flash to your own taste

I'm sorry. I should have asked what "metering mode"?

Evaluative, center weighted and partial.

I changed the original post title and description.

I have a 350D (XT) and I find that evaluative metering usually works pretty well. I rarely feel the need to use partial. (And I'm not sure what the point of centre-weighted is.)