TortoiseCVS lets you directly check out modules, update, commit and see differences by right clicking on files and folders within Explorer. You can see the state of a file with overlays on top of the normal icons within Explorer. It even works from within the file open dialog. You can perform tagging, branching, merging and importing, and you can go directly to a browser web log (using ViewCVS or CVSWeb) on a particular file.