Bitcoin + the merged coins (DVC, iXC, and NMC) are always a good choice. PPC, LTC, and XPM are also not bad ideas.
merged coins? I've heard of namecoin but not the others...
DeVcoin and iXCoin can also be mined with NMC and Bitcoin at the same time. They aren't terribly valuable, but they are extra cents for no extra hashes so why not? Bitparking has a great pool to mine on too, mmpool.bitparking.com.