Git
Recently I have been on the Git bandwagon (I've used SVN and Mercurial). So far I really like what I get with Git. It is far from a pain to setup and more development tools are starting to adopt using it.
It's a distributed version control system. This allows for us to have our own independent trunk-like area. I can work in my own area and invite you over to view changesets very easily. I can rollback in my own space without mucking up the central repo. I can commit, branch, and do everything you can do with SVN locally. I really like having this control.
With SVN, you need access to your repo in order to commit. What if you're on the road or at a cafe with no internet? Not good.
Sure, SVN is much simpler to learn but I think the advantages of distributed source control largely outweigh the fact that it has a little learning curve.
I also like that it is smarter about merging.
A major downside of GIT is that it stores the entire history locally. (Yes, you can perform surgery to cut that down, but it's the default behavior). It's not a problem at all for source files, but if you have a large project with gigabytes of asset data, it becomes a problem quickly. In my current experience, I'd recommend GIT only for smaller or source-only repos.
If you're still curious about GIT, check out http://whygitisbetterthanx.com/http://thkoch2001.github.io/whygitisbetter/ for some good information/metrics. Also check see https://git.wiki.kernel.org/index.php/GitSvnComparsion