You can use http://www.coinwarz.com to see up-to-date mining profitability charts that compare all the actively traded cryptocurrencies.  There's always a lot of fluctuation in which is the top cryptocurrency every day, and it's caused by the constant flip-flopping of miners.  Personally, I'd recommend picking a few currencies that you think could do well, and go with them.  If you have the hash power, Litecoins are very stable in their profitability.