Microsoft's Template Engine
Microsoft is shipping T4, an ASP-like template engine. It's included in the 'Guidance Automation Extensions' and with the DSL tools package now part of the Visual Studio SDK, so it's free.
Actually, it looks it maybe redistributable, and in that case, as far as I know, will be the first template engine that can be freely redistributable. The 'maybe' is because the EULA is not very clear. I hope it will be more specific in future releases.
My fellow Visual Studio Wizard wrote a T4 editor for VS 2005 that includes several cool features. If you are working with the GAT/GAX, with DSLs or using T4 for generating code in other context, you should be using it.