IE8 and IE9 are indeed much better. Unfortunately, IE6 still has a presence in much of locked-down Corporate America, and I get hits in my logs from both IE5 (!) and IE7.
As for ASP.NET, I hear about it, but I've never see it outside of a book or a blog post. I'm in Silicon Valley, so that certainly biases things. I know of people who use it (e.g., the Stack Overflow team are happy using a subset of ASP.NET), but it's always somewhere else. In my world, Nada. Ditto anything else running on IIS. I could reach out and touch boxes running IIS in 2002. Now they're completely gone. That's a huge shift.