It’s surprising how difficult it is to design a good user interface. I mean a really great user interface, not like the rubbish most programmers come up with when asked to design a UI. They just don’t think about how things are going to be used. (Apple can, of course, pat themselves firmly on the back for being good at this, but most other companies should take a look and see why their interfaces are so bad).
As for me, I’ve spent a great deal of time recently thinking about UI issues; my current dilemma is something of a horizontal vs. vertical problem… I have two user interface elements, one of which would look best horizontal, and the other of which would look best vertical (because it is a list of items, so a vertical layout will provide more space for the items’ information). Unfortunately for me, they both have to have the same orientation (because of the way they interact). At the moment I’m leaning towards vertical, but we’ll see.