Here's the secret to finding the holy grail of digital currency investment.

First realize that before Google, there was a search engine called AltaVista that dominated the space. It makes sense that other digital currencies will emerge to compete with and eventually surpass bitcoin in terms of popularity. Look at bitcoin as a blue chip rather than a growth stock. Now start researching to find the alt coins with the best chance to compete with bitcoin. Then pick two or three and invest small amounts in each one. Then work your ass off to help the communities build these currencies as you watch your investment grow.

https://bitcointalk.org/index.php?board=67.0

Try looking here: http://www.drillbitsystem.com

Do not mine if you expect to win money.
Or try crapcoins.

Do not mine - difficulty is too hig - you can try scrypt mining alt coins.