Right now (and in no particular order).
PPC - Peercoin
LTC - Litecoin
DGC - Digitalcoin
SRC - Securecoin
CGB - CryptogenicBullion
Peercoin has a good long-term potential as a currency. As an investor Proof-of-Stake is a good option for you.
Litecoin is 'silver' to bitcoins 'gold'. Enough said.
Digitalcoin unlike similar alt. coins did not have a pre-mine, has a good developer and has much potential for growth. CryptoAve exchange is coming.
Securecoin is perhaps the most underrated alt. coin in existance. Its basically Quark (very secure) using Bitcoins proven economic model. Also built by the digitalcoin developer with a fair launch.
CryptogenicBullion is your bank vault or high-interest savings account. Another Proof-of-Stake coin. Rarity and Scarcity is a good investment choice. Other coins have attempted this and are perhaps to rare in comparison. CGB seems to have got the balance just about right. Also has a good development team.
Other's you had mentioned:
Worldcoin and Megacoin have potential, but right now DGC has more potential as an investor.
Feathercoin is a Fork of Litecoin -
http://cryptolife.net/an-in-depth-look-at-feathercoin-the-coin-that-started-it-all/ (Hazard is an interesting character - the critiques and information on that blog are very accurate to date - well worth reading imho.)
Watching Quark and Stablecoin. Anoncoin is to often overlooked ! Datacoin has potential, although it's early days.
Anyway, with my current top 5 as your alt. coin portfolio - I think you could pick worse - However, this is not investment advice.
