Are there any Lisps you would recommend (other than Clojure)? (Or languages?)
Clojure is probably the best bet. I don't know much about it but lots of people seem to use it, and any decent Lisp that lots of people use is probably a good bet.
Why not? Have you used a language other than Arc to write a web app recently?
If writing web apps in other languages isn't still painful where have other languages/frameworks caught up?
It's still missing some things that most people take for granted.