I've been doing a lot of Ruby on Rails dev work lately, and the framework tends to generate a lot of files. Until recently, I was using a combination of "svn status" piped into grep, awk, and xargs to accomplish adding new files recursively. A friend recently told me to check out the following solution instead.
svn --force add *
The only negative side effect I can see is that it seems to add ignored files back into the tree. This is mostly a non-issue for me, but take note.