1. Look at the MVC framework for ASP.NET 3.5 as it makes ASP.NET act more like Rails
2. If you're going to use ASP.NET, use 3.5 so you can use LINQ and all the new 3.5 features. It makes your life WAY easier.
3. There is no real scaffolding for ASP.NET like there is in RoR. Well there is a kind of like it thing that was put out (http://www.hanselman.com/blog/PuttingASPNETDynamicDataIntoCo...).
Now, here's my take... if you learn ASP.NET/C# you will have marketable skills in most non silicon valley markets that you can use as a consultant or employee as need be. There are significantly less corporate jobs that are RoR than there are C#/ASP.NET.
Also make sure you look at Python/Django (which is normally what is argued with RoR).