Question: What are some key bindings that aren't included?

Answer: 
You can find the complete list of limitations in MonoTouch at [Xamarin](http://docs.xamarin.com/ios/about/limitations). 

A short list of .NET features not available in MonoTouch:

* The Dynamic Language Runtime (DLR)
* Generic Virtual Methods
* P/Invokes in Generic Types
* Value types as Dictionary Keys
* System.Reflection.Emit
* System.Runtime.Remoting
One thing to also mention is you cannot reference .NET assemblies that haven't been built/compiled using the .NET MonoTouch configuration.

So if you have a favourite .NET 2.0 library you will need to re-import the source into a new MonoTouch project, compile it, and then reference it. There may be an easier way of doing this by editing the `.csproj` file but I haven't found it.