I am developing an ASP.NET MVC application and I want to use OpenId.
What is the best option?
I'll second the recommendation for DotNetOpenId and add a recommendation for openid-selector (open source version of idselector)
We use the excellent DotNetOpenId library here on Stack Overflow:
http://code.google.com/p/dotnetopenid/
now moved to:
http://www.dotnetopenauth.net/
Our original login UI was provided by ID Selector, but we've since rolled our own minimalist version.