my boss is one of those people clients ask for to do it and he has a CS degree. just my .02

realizes that came out odd. My boss is recognized as a leader in interface design and he has just a CS degree, sorry.

one of my girlfriends is getting her masters in usability, which seems to include some UI work, but also many non-computer things.

She's a programmer, though, and will probably combine the two to do design work. (that is, making UIs.)

Ergonomics?

web design?

BSCS with minor in graphics arts would prolly be ideal. Depends though whether the employer wants you to just do the design and write a spec

for software engineers to implement, or if they want you to actually DO the implementation.

Psychology helps too, if you're talking about making an optimal UI that people will naturally "get".