I did an undergrad in engineering physics (computer and electrical option) after starting in mechanical engineering and deciding it wasn't for me. I enjoyed the hell out of it, intellectually speaking, and would do it over again in a heartbeat. Maybe I would try a little harder and benefit more from it... :-)
My undergrad was never directly applicable in my career, apart from the fundamental analytical / thinking skills and strong basis in math and physics, which have all been supremely useful to me. I've gone on to do a couple more degrees (masters and doctorate, plus a stutter start at a different masters) in completely unrelated fields, and I would do them all over again too.
Whenever I retire, I would like to go back to school again for something different yet again. I enjoy the intellectual stimulation and challenge school brings, even if my screen name and posting history may suggest otherwise...