I am an avid Mathematica user. Not because I need to evaluate that much math, but because I really like its wysiwyg notebook structure for note-taking. It's great for keeping up with lectures and including decent looking equations and tables when they come up (which is fairly often in technical classes). The export to latex is a nice added bonus.

As far as I know, there aren't great alternatives to the Mathematica front end - I'd love to be proven wrong, through.