If you use Subversion on your Visual Studio development projects, you've gotta try VisualSVN.  You can find it at: http://www.visualsvn.com. 

I've never really been jazzed by Visual Studio plugins for source control.  They've always left me with a kind of "so-what" feeling.  They tend to bring too much un-useful visual clutter the solution explorer, and they haven't really brought any compelling functionality to bear on the problem that wasn't done better by something like Tortoise.

VisualSVN isn't one of those typical plugins.  VisualSVN takes a novel approach to bringing SVN into the Visual Studio IDE... it brings Tortoise into the IDE!  Rather than switching to a Windows Explorer window to use Tortoise on your source tree, VisualSVN simply opens the appropriate Tortoise screen as a modal window over Visual Studio:

VisualSVN adds a menu to Visual Studio where you'll find the usual Tortoise SVN commands like Update, Commit, Show Changes, Repo-Browser, Show History, Revert, Cleanup, etc.  It adds a Disk Browser menu option that opens Windows Explorer (and thus Tortoise) on to the source tree on the file system.  It also has a menu option called Set Working Folder Root that lets you do just that.

The simple elegance of this menu option speaks of the attention to usability that the VisualSVN team has put into thinking about the problem that the product solves.  It's not that VisualSVN has a lot of bells and whistles, it just works well.  You can tell a product that has great usability by how much you don't notice it when you're using it.  VisualSVN is definitely one of those products that makes it look easy.  Re-leveraging the existing well-proven Tortoise usability is a real win for Tortoise users and yet-to-be Tortoise users alike.  VisualSVN brings an effective simplicity to using SVN in Visual Studio.

VisualSVN puts the right Subversion and Tortoise tools in the right place.  The context menu in the solution explorer provides useful tools like Revert, Edit Conflicts, Show Changes, Show History, and even Blame, Get Lock and Release Lock.

My favorite feature of VisualSVN is its intelligence in re-loading Visual Studio projects when an update changes the project files.  Although I'm curious to see what would happen if an update caused a conflict on a project file.  This happens so very rarely, that I suspect it's not really worth providing special tooling for.

VisualSVN will set you back a whopping $19 USD, after a 30-day trial period.  You can download the trial from VisualSVN download page: http://www.visualsvn.com/download.html.