Various Rakebacks

I've been playing for a while now and have existing accounts at pokerroom and party and just recently have been reading up on rakeback on certain sites.

If anyone could give me a rough estimate of the added profit you get from the rakeback on most pokerrooms, and if possible the best rakeback site where I can mah monay from [img]/images/graemlins/smile.gif[/img]

Thanks.