The only alt-coin I have faith in is Litecoin.
I have about 500 LTC stashed away in the hope that they someday become the silver to bitcoin's gold.
Saw a little spike in value with yet another rumor about LTC being available on MtGox, but then everyone lost patience and it's back down to around 2.5 USD again.
Long way to go before I make up my losses, since I bought in at 3.8!
Why the predeliction to mt gox for trading? Other exchanges are way more flexible and will allow trading other alt-coins. I like Virucurex the best. coin "A" to coin "B" to coin "C" to "USD" if I want.
https://vircurex.com/ Yep, mt.gox is a fiat<->btc exchange (when you can deposite USD, that is). There are plenty of established altcoin exchanges. Btce and Vircurex have worked well for me before.