I'll also chime in for BitShares.  When I first heard about 'Protoshares' - I was skeptical.  However, I've been researching and following this development for the past 10 months, daily; and am completely blown away.  This platform is the bitcoin killer, and I don't say that lightly.  Think of any problem any other crypto has, and I'd challenge you to find out if its not solved through the BitShares platform.

The 3 MAJOR issues I believe BitShares has solved are:

• Transaction times - 10 seconds. On the dot. No more of this 10 minute confirmation [ON AVERAGE!] B.S.
• More decentralized than bitcoin by orders of magnitude - there are what, 5 mining pools?  BitShares secures the network through DPOS (delegated proof of stake), through 101 delegates that are elected.  You choose the good guys, the bad actors simply cannot sustain their efforts. [also a hat tip to the US founding fathers...1776]
• Volatility - With the coming advent of user-pegged asset markets; one can store their value, cryptographically, in an asset that has relatively low volatility in comparison to bitcoin (i.e. the US Dollar - this will be 'bitUSD')

BitShares is your 'savings' to your bitcoin 'checking' and MUCH MUCH more.  I cannot say enough good things about the core team and their efforts as well.  Good people doing it for the right reasons, not hiding behind pseudonyms, because they don't need to.