what language should I learn next?
mdasen: This is going to be unpopular advice, but I would suggest algorithms in C.  You already know how to make web applications.  Any reason you want to know how to make web applications again?  Will Lisp or C web applications make you happier or more productive?What will help you is probably a better understanding of algorithms/programming and I personally like C for that job.  C doesn't hide stuff like higher-level languages do.  It makes you think about how the computer processes the information and uses memory.  I'm not suggesting that you ever use C for one of your webapps.  I'm suggesting that knowing C and good algorithms will make you a better programmer in higher level languages because you will understand more.