Stole the title for this thread from a post by Thurber, I think it would make an interesting topic as opposed to that other thread that's been dragged into the ground.
I know for me the challange on the interface is getting good graphics and icons to spice it up with. But the chalange might be different for you.
I'm interested in peoples thought on how to go about creating good interfaces as well as what you think is hot and what's not.