I've worked with svn, cvs, vss, and now I'm working with perforce. I use to work with baazar for my personal projects, and I have tried git and mercurial.
I don't recommend you perforce at all, and of course i don't recommend you VSS either. It's insecure, unreliable and impractical to work with. It's model it's much more twisted than svn, cvs, git, .. etc .It is also more difficult to use with scripts (as you have to deal with views, clients, and other system variables).
I would recommend you svn with any regular issue tracker. You can customize it throught svn hooks as desired.... In some cases it would be interesting to go distributed (git, mercurial, baazar), but if you don't have an opinion yet, you should start with svn ..
well, thats my opinion of course...
