While at Yodobashi Camera helping my friend pick a calculator I noticed Casio now sells 3 models of USB calculators. It seems like an obvious idea. Instead of buying a separate keypad or a calucator that only prints just get one of these and cover all bases. The USB cables fold inside so if you want to use it just as a caluclator it all folds up and you can't tell the difference.
While I'm at it Casio also sells a CD printer. It prints directly on the CD.