I vote Ghash with Eligius as a backup.
Even with the increased hashpower it will be nearly impossible to ROI at this point. We can't afford be paying 2% to BTC Guild and Bitminter only has 1% of the network hashrate and a 1% fee. Ghash has zero fees and the highest hashrate. With the rise of Discus Fish, Ghash isn't a 51% attack threat anymore so there is no need to feel guilty about using it anymore. Eligius also has zero fees, a solid hashrate and pays transaction fees to miners.