Save the nice bike for riding for fun. Buy a $50 bike and a $100 lock. Get a crapola bike at a second hand shop or out of a dumpster for riding to work. Upgrade the wheels to reasonable quality alloy rims and hubs when the originals start breaking, but leave the bike as ugly and scratched up as possible. Also get decent saddle (cover with an old plastic bag to keep the rain off), and decent handelbar grips. Paint the bike with black metal primer. If you have any quick releases on the wheels or seat, lock them closed with hose clamps.

Nice wheels and tires and proper maintenance will make the bike good to ride, but not attract attention of theives. Make it so it is not worth a theif's time. Riding home on a crummy bike is less of a bummer than walking home because your nice bike got stolen.