It is more like there are 10 coins created every minute and hard to keep up (let along find a nice block explorer plus exchange for the coin). Plus many coins don't get on an API with an exchange so I can't list them (CoinEx and PhenixEx don't have API's yet to get order data). I try to have every coin on Cryptsy, BTC-e and BTER.com with the exception of the CPU only coins (because they don't lend themselves to a good comparison between GPU mining coins).
What coins specifically am I missing?
I was speaking to Zetacoin when I made those comments, and you have since added it to your list. :-) So allow me to 'eat my words' on that comment.
But I understand new coins popping up *constantly* - and I hadn't thought of needing an API to put it into a sensible list.
Off topic: My other favorite that would be nice to see on Coinchoose is Primecoin. But that is probably a can of worms.