Look for a bike that does more for you than "it would be nice." I can't imagine incurring the wrath of the wife unless the bike just screams "You can't live without me!" at you.
Edit: For instance, a bike where you get to build it up from the frame would be worth the cost to me, but buying another bike just because seems like a recipe for having a pile of bikes in the garage that I don't ride much anyway.