there's more to it than just what kind of cable you use... CAT5, 5e, and 6 all have fairly rigorous installation standards that must be met for an installation to meet spec. This is normally only a real issue in commercial installations, though. For home use, you're probably going to be just fine using CAT5 without any special considerations, you'll be able to run 100BaseT OK.
Taking my Category 5/5e, 6, and fiber optic Technician and Designer Certification exams in a few weeks...