I recently received my Netduino
Netdulino is a small computer designed for interfacing to hardware. It is very much like the Ardulino only with a faster processor (32 bit rather than 8) and supports the Microsoft .Net technology.
.Net is a really good match for this sort of board as the CLR is designed to allow for code to be compiled at deployment time for any processor with a CLR compiler. So in theory programs written in .NET could be moved from one Netdulino to another without the need to access the source code.
.Net also provides a full features programming environment (Visual Studio Express is free) and you can even choose between imperative (C# / Basic) or functional programming styles. These are full featured compilers with no compromises. You don't have to spend your time thinking about weird restrictions on integer sizes, register use or whatever. Any C# source will work fine without modification.
Getting started was pretty quick once the files were all installed. I had the LED blinking in about half an hour, most of which was spent downloading stuff.
The only drawback with this approach is that once you blink the LED there is not much more that can be done without getting some electronic components to interface to. I have ordered some LEDs, motors and a grab bag of other stuff from Jameco and Solarbotics.