It depends on your clients and/or the work you're doing. On the server-side, I do almost entirely ASP.NET work for small and medium business. Much of that is pu

It depends on your clients and/or the work you're doing. On the server-side, I do almost entirely ASP.NET work for small and medium business. Much of that is public-facing and you wouldn't know it was .NET unless you viewed the source and looked pretty closely. You certainly can build drab, enterprisey software with ASP.NET (or any other language), but you can also build sites like Stack Overflow just as easily. Trying to host an ASP.NET 4/MVC3 site on Apache would be a nightmare. So, for the same reason you might tend to avoid IIS for your PHP work, .NET developers will prefer IIS for their work. As for why so much "enterprise" software is written in languages like C# and Java, I believe it has a lot to do with those companies having very large teams with high turnover. Static languages (and their tooling) do have some compelling advantages in that situation.