Litecoin is first altcoin but not the best for sure
Which is the best altcoin then?
Nextcoin (Nxt) is the only coin in the top 10 that has been rising in total market value lately acoording to: http://coinmarketcap.com/ It is not very profitable to mine however.
Until a few days ago dogecoin was definitely worth getting into. But since yesterday prices have plummeted and it is unlikely to recover.