After years of Windows Forms development, we started shifting to ASP.NET for the last 2 years. We've considered using WPF and Silverlight for some projects, but wisely decided not to. Of course, I didn't expect Microsoft to reduce its plans for Silverlight, but it has once again confirmed for me that we made a good decision to go for web development. We're not really using a lot of HTML5-features, so you could say we're just using HTML(4) + CSS + JavaScript. And I don't care about the hype of "HTML5", I just want to use what's available and try to make great products. We're still using Microsoft technologies in the back-end (SQL Server, IIS, ASP.NET), but the client-side is totally independent of Microsoft.