This is a question for both DMs and players. How do you use voices when roleplaying? Do you consider yourself a full blown voice actor, with distinctly different voices for each character? Do you just use your regular voice? Something in between? If you use your normal voice, how do you communicate when you are talking in-character or out-of-character?
I do a certain amount of voice acting, both when I play and when I GM. As you note, it is good to differentiate between when the character is speaking, and when the player is. It's also kind of fun, even if my vocal stylings aren't professional-quality.
Just this summer, I was in a weekend-long live action game, in which I kept up a bad Russian accent. Because:
1) I don't know accents well enough to do a good Russian accent.
2) The character wasn't actually Russian, so it was reasonable that his accent wouldn't be great, and I could denote when he'd dropped the facade by dropping the accent.