I've been very happy using svn against a remote repository + using mercurial or git as a local repository on top of the svn repo.
They're both distributed source control tools, and I like them both for slightly different reasons.
I've found it to be very powerful to use my own local repo that coincides with a remote subversion repository...
Update
Although I really like the answers about exporting from google code, and importing to your local repo, what I really like about the combination of svn and git/mercurial is that you can periodically do an svn update to get the latest code from google, and then to a git commit or an hg commit to add the latest code to your local repo.
Much simpler than periodically doing an svn export into your repo to get updates.
Additionally, using git/mercurial, you have powerful branching/patching tools available that svn doesn't make so easy.