 <p>All of .net is available in the .net SDK, so in theory you will not need Visual Studio at all.</p> <p>Now, there are some things that Express will not do. For example, the Database Designer is not very comprehensive and adding different remote databases is not or only very hardly possible. Still, in code you can connect to everything.</p> <p>There is also no Remote Debugger, no support for creating Setup Files (well, that does not apply to ASP.net anyway), no real Publish Web Site Feature (although that can be <a href="http://blogs.msdn.com/b/jamesche/archive/2007/09/27/automating-aspnet-compiler-in-visual-web-developer.aspx" rel="nofollow noreferrer">added manually</a> as it's just a Frontend for a SDK tool), no integrated Unit testing (and Microsoft <a href="http://weblogs.asp.net/nunitaddin/archive/2007/05/30/microsoft-vs-testdriven-net-express.aspx" rel="nofollow noreferrer">loves to threaten people</a> who add it), etc.</p> <p>For a full comparison, see here:</p> <p><a href="http://msdn.microsoft.com/en-us/vstudio/products/cc149003.aspx" rel="nofollow noreferrer">Visual Studio 2008 Editions</a></p> <p>But as said: Functionality of .net is all in the SDK, Visual Studio is just making it a bit easier to work with.</p>