Here is a great DotNetRocks podcast episode where Mark Miller talks about how to create Good UI; Even though the show title is .NET rocks, this episode talks about a general rule of thumbs on how to create a UI to increase program user's productivity.
Here is an episode exerpt
Good user interface design can be done by sticking to some good rules and avoiding common mistakes. You don't need to be a latte-sippin tattoo-wearin macbook-carrying designer to create user interfaces that work.
