I was playing around with the brand new Visual Studio 2010 and have found a really cool new feature. Actually this is something I'm waiting for years.
Every new Visual Studio version requires you to create a new project and maintain it along the other versions. I had a situation once that I need to keep VS2005, VS2005 and VS2008 projects. What a pain! As soon as you add a new class to your project you need to replicate that to the other versions. It was chaotic!
The new feature:
VS2010 have introduced a new cool feature called "Platform Toolset". It allows you to target your build using specific VS libraries which allow you to build binaries as if you are using previous VS versions. Natively it comes with v100 and v90 platforms (v100 is the default). I did some testing targeting v90 and it really works. The generated DLL (in my case an ARX module) was totally compatible with the Host application (in this case AutoCAD).
More than that, with the ability to create your custom targets open a totally new world of VS projects management which will save you hours copying thing to keep your source code updated.
VS 2010 Enhancements
VS 2010 native Multi-targeting
I have used Visual Studio 2010 Professional Trial version to test this and you can download it from here:
Visual Studio 2010 Trial Download