Everyone knows Doge is a joke - good for short speculation but unlikely to sustain long term traction.

Worldcoin has good marketting but not much else particularly innovative to differentiate it - as for FIAT access Quark already has that through several exchanges.

Besides which lots happening with Quark.

Just today: QRK on BTC38.com the largest Chinese exchange.

For more see:

http://www.reddit.com/r/QuarkCoin/comments/1vl9lo/china_loves_quark/
http://www.quarkcoin.cc/

Frozen looks like a Quark fork. Limited supply may help its value. If you're interested best get on board before Cryptsy add it.

As for me I like QRK, good community/developer support, strong support outside the crypto community.

Also interested in 2nd gen crypto's like nxt and mastercoin with explicit decentralised p2p exchange support.

Memorycoin looks interesting too.