I dropped >$1000 on my bike, and I use the Kryptonite NY Lock Fahgettaboudit (3'3"). It's the highest rated (12/12) lock+chain they sell, but also the heaviest (8.4 lb). Removing the front wheel for locking would be the cheapest way to go. I keep it in my Xtracycle's Freeloader when in transit.
Tip: Any college campus is a bicycle high-theft area.
Tip: Put the lock portion around your bike frame so a thief can't smash it against the ground.