Besides all the polished SHA-2 and scrypt coins out there, there are also interesting projects like bitshares, protoshares, eMunie and NXTcoin. I invested in NXTcoin and I'm planning on investing in eMunie, it's a risky gamble though.
If you want to invest in altcoins then make sure to invest in at least a few promising coins. Lets say you invest in 10 coins, if just one of those coins skyrockets you will still make profit even if all the other coins become worthless (which is very unlikely).