I’m not currently using Subversion on a day-to-day basis, but if I was I’d definitely be keen to have it integrated into the Visual Studio 2005 IDE (even SourceSafe, the enfant terrible gives you this ability!), rather than using TortoiseSVN, which integrates into Windows Explorer. Back in January this year (2007), Arild Fines released version 1.0 Final of AnkhSVN, a Visual Studio 2005 plugin for Subversion. You can download it here.
The source code is also available for free, and there is a AnkhSVN Wiki.