Original: @Rob, TFS has something called "Shelving" that addresses your concern about commiting work-in-progress without it affecting the official build. I realize you see central version control as a hindrance, but with respect to TFS, checking your code into the shelf can be viewed as a strength b/c then the central server has a copy of your work-in-progress in the rare event your local machine crashes or is lost/stolen or you need to switch gears quickly. My point is that TFS should be given proper praise in this area. Also, branching and merging in TFS2010 has been improved from prior versions, and it isn't clear what version you are referring to when you say "... from experience that branching and merging in TFS is not good." Disclaimer: I'm a moderate user of TFS2010.
Edit Dec-5-2011: To the OP, one thing that bothers me about TFS is that it insists on setting all your local files to "read-only" when you're not working on them. If you want to make a change, the flow is that you must "check-out" the file, which just clears the readonly attribute on the file so that TFS knows to keep an eye on it. That's an inconvenient workflow. The way I would prefer it to work is that is just automatically detects if I've made a change and doesn't worry/bother with the file attributes at all. That way, I can modify the file either in Visual Studio, or Notepad, or with whatever tool I please. The version control system should be as transparent as possible in this regard. There is a Windows Explorer Extension (TFS PowerTools) that allows you to work with your files in Windows Explorer, but that doesn't simplify the workflow very much.