In terms of geography, it's pretty much a mix. Much of the Russia population lives in the part that you could categorise Eastern Europe or Central Asia, so that part's a toss up. Siberia is a large part of the Russia, but I'm sure you know it's famous for it's sparse population due to it's climate and terrain. In terms of demographics, Russians are usually divided into the European caucasian type, and the more in-tune with traditional 'Asian' looking type, with Mongolian or Chinese in their heritage.
At least from what I know..