Has anyone calculated which hashing algorithm has the LEAST advantage from a GPU vs. CPU?

I'm always in search of the best coin to mine on all but 1 of my cores along with my GPU miner.

I got ~3 XPM in 1 week mining on RapidPrime with their optimized CPU miner with my i7-3770 @ 3.4 Ghz x 7 cores and am curious if I can do any better.