Within the last year I have become addicted to subversion. I am an only developer and I also work on a few of my own projects. With SVN its really easy to manage everything
I also personally would stay with Subversion, Is there anything better?
Subversion is a great version control system, and you're happy with it, so if you are looking further, I can recommend you to get some info about Continuous Integration, there are many tools out there that can help you to make automatic builds, make your builds self-testing, check the integrity of each commit, and much more...