I have used both at work and at home. They are both very cool in their own right. The only time i would recommend using TFS though is if you will be using more of the features than just the source control. If all you need is source control you cant go wrong with SVN and this is why.
VisualSVN Server That is a full SVN server with a nice plugin to manage it with. It lets you use windows authentication right through the UI. Easy.
Tortoise Its tortoise, enough said.
ankhsvn It is a great SCC plugin. For those that want full VS IDE integration the latest version is a full SCC plugin. So you now get full integration for free.
The above set up is 100% free and will get you through anything you need for source control.
