Ripple. Its more stable and is being adopted by financial institutions (AMEX being one of the biggest so far). I honestly think it'll be the first widely used crypto. Its a little different from Bitcoin, but I think it'll do well in the long run.
Isn't ripple centralized?
So yes, its a little more centralized than Bitcoin, but everything I read really gives me the impression that they're handling things in the right way, so as to have a balance between network performance and distributed safety, without any one person/group being able to manipulate the ledger. So there'll never be any mining farms that can throw their weight around.
If anyone is really curious, do your research and I think you'll find the tech to be pretty interesting.