Not on the 360. You will keep most of your settings (IIRC you'll need to set Match Frame Rate back to "On" and the Dolby Audio back to whatever you had it set to - if you haven't touched these settings then this won't apply) and all your recordings, series links, profile settings, etc. It will, however, reset Netflix, Amazon and iPlayer - you'll need to sign in again.
Basically a discussion as to whether it's a "real" reset or not! It's more of a "refresh" than a reset. A full reset can apparently be done but requires instructions form Customer Service as to how to perform it.