I did look at Subversion as part of this project, and I've heard lots of good things about it. It certainly has some features I'd love to have (atomic commits & easy renaming come to mind). But it seems more complex to install than CVS, and we already have a working CVS installation & are familiar with it. I also am not crazy about the fact that it requires a webserver (Apache 2 at that IIRC). We are using mod_perl w/ Apache 1.3 and I'm not very interested in adding a 3rd server into the mix.
Subversion is definitely something I'll keep my eye on for the future. But I don't think it's the answer for right now, at least at work.