For CPU mining, I think the best candidates should be Monero (XMR) and Magi Coin (XMG). If you have some HDD, you may think more about Burst Coin, it use the power of CPU to check/read nonces.
You also could mine Vert Coin (VTC) with CPU. But you should keep in mind that XMR and VTC we could use GPU to mine as well, and their difficulty level's already very high now.
Thanks, will try mining Burst Coin and let you know the result.