What startups here are focusing on developing on top of .NET?
tjmule: The start-up I work for (http://www.theport.com) uses .NET 3.5 / C# / SQL Server 2005. We've incorporated some open source projects (most notably SOLR, NHibernate, and SharedCache) and use a wide range of open source tools for day-to-day management of our team (SVN, Trac, CC.NET). We've found great success in getting .NET to scale and in rapid development.I've been developing w/ Microsoft since the VB6 days and I will be the first to admit that there's no right answer to which is the "best stack". There's great advantages to LAMP, Java, and Microsoft. I think it all depends on where your comfortability lies. My honest opinion is that trying to answer this question is like to trying to figure out which is the "best religion". It's totally subjective.