NXT - 100% proof of stake, pretty new coin, price has been dipping lately, not a bitcoin fork.  Anonymous Russian devs, and many other volunteer devs.  A lot of its competitors feel like VC backed wannabes by comparison.
BTC - The king of cryptos is probably the safest bet, but may not rise as quickly as a successful altcoin
PPC - Peercoin Proof-Of-Stake/Proof-Of-Work hybrid coin.  Innovative altcoin.  Price has seen a nice steady rise.
DOGE - Risky.  It seems like an old overdone joke, but the masses sometimes love old overdone jokes and good viral marketing may be the only think an altcoin needs to separate itself from the pack and succeed.