There's no right answer to "What technology should I learn next?" But there is a way to manage your skills to maximize the return you get from them.
You don't have to give up using dynamic SQL just because you're using Entity Framework. The Entity Framework SqlQuery method will give you back the flexibility of dynamic SQL and still let you work with your data in an object-oriented way.
If you really want to take full control of the exceptions you pass to your clients, you can write your own Exception class. Here's how to do that, complete with support for additional properties.
A complex ASP.NET MVC form can drive you to a big, ugly action method that handles all the functionality the page offers. The ActionMethodSelector provides a clean way to separate that logic over multiple methods, provided you understand a key distinction of which many ASP.NET MVC developers aren't aware.
If you're creating an XML document and want to write code that you'll actually be able to maintain … well, it may be time to learn a little Visual Basic, just so you can use XML Literals. It's a good solution even for C# shops.
Peter shows how a Visual Studio database project can make you more productive when making changes to your database. But a database project also gives you a variety of tools to let you keep track of what those changes are -- which will make moving those changes to your production environment considerably safer.
The developers building new applications are very nice people, of course. But the real heroes of the programming world are the developers maintaining and extending existing applications.
Peter learns something by listening to readers: Visual Studio database projects provide a great environment for making changes to your databases. Here's a brief introduction about how they'll make life easier for you and all the steps for setting one up.
Peter responds to a question: How, in an ASP.NET MVC form, can the user be given two submit Buttons that do two different things?
Reactive Extensions will let you catch interim results from a long running process. Coupled with the Microsoft .NET Framework 4.5 support for asynchronous processing, you don't even have to lock up your client while you process those results.
Peter explains why he doesn't believe in "responsive designs" that allow a single application to work in both the desktop and mobile environments.
When you have a process that can return multiple results over time, then .NET Framework Reactive Extensions will let you simplify your code and manage it better.
Creating a full-featured extension for the ASP.NET MVC HtmlHelper class sounds like a lot of work. But, because of the way the Microsoft .NET Framework works, it's almost trivially easy. To show that, here's an EditBlockFor method that adds a label, a textbox and a validation message to your ASP.NET View.
Here's a grab bag of what you might find useful in the next version of the .NET Framework. It's good news for everyone but ASP.NET Web Form developers.
Peter returns to improve performance by splitting a single table into multiple entities, but this time, he implements his solution using the Entity Framework 6 designer.