It's a shame to see how the top 10 market cap of coins is full of questionable coins which don't deserve this place, or even worse, literally scams coins.
Currently the only serious coins in that list are Bitcoin, Litecoin, BitShares and Peercoin.
Ripple: their gateway system can be interesting for remittances, but a coin where more than 70% are in the hands of its creators?
Darkcoin: the reward per block never matchs the intended formula:
https://i.imgur.com/1KyeATF.jpg They also changed the formula various times and the max coin supply later in order to benefit who mined this coin in the first hours.
Stellar: it sounds like a random Ripple clone, it never explained what is doing here.
Dogecoin: used the stupid innovation from Luckycoin, which is the random rewards. Lately they realized this was a bad idea and fixed it.
NXT: they closed the IPO without previous warning:
https://bitcointalk.org/index.php?topic=303898.msg3620732#msg3620732Paycoin: a scam coin from GAW, with 12 million of premined coins, false partnerships to increase its merchant acception and a lot of other lies.