No, seriously, what is the best distro for web applications?
wheels: I'd say pick the distribution you know best, with a few provisos:  - It's one of the major distributions
  - It's not Gentoo

I used to use SuSE on servers because I knew SuSE best, and before that Redhat for the same reason.  Now I use Ubuntu.  All have been fine.  Worst case is getting something on a server that you don't know how to configure.