i would avoid something too nice or expensive if it's going to be a bike you lock up outside. if it's gonna be a grocery getter, i'd look for a old road/touring bike or rigid mtb on craigslist. i'd especially look for something with eyelets for racks and fenders.

edit: i hear mixed reviews about the alfine internal gear hub. i near nuvincis are decent if you don't mind a heavy(!) hub. rohloffs are pimp but $. i think i'd go with a normal chain and derailler setup

edit again: does your hardtail have a rigid fork? is there something about it that isn't satisfactory? hardtail mtbs (especially with rigid forks) make some pretty pimp commuter/beaters. can it take a rack and fenders?