To the developers of Ethereum,
You are building a really interesting project and it is the only other project in the cryptocurrency space (other than Bitcoin) that has actually piqued my interest. Now, obviously it is early days and there is a lot of work ahead of you. What is clear, and I really mean this with the utmost respect, is that you are not user interface designers. The client looks highly technical, lacks basic usability measures and is quite clearly not what you should be spending any time on. I recognise that in fact you probably already know this and haven't spent a lot of time on the UI, other than to provide an interface by which to test the network and protocol.
My suggestion is this. Provide a client that is not windowed and exposes all of its functionality via a REST interface, and allow that to be the way a real user interface can interact with the local client. By doing this you remove the burden from yourselves of having to spend time developing user interface code, and you pave the way to contributors (myself, for example) who would like to experiment with building a custom user interface on top of the exposed REST interface. I would suggest also that the mining process should be able to be activated and controlled from the REST interface, or at least expose its own REST interface, similar to the main client. I believe doing this will make it a lot more feasible for the Ethereum ecosystem to grow and flourish.