Properly securing a bike is a headache and a half. Sure, a decent U-lock might keep your frame from getting stolen, but then a wheel or two might be up for grabs, not to mention your saddle. Short of avoiding quick release fasteners (which is a good idea regardless), there’s Seatylock, which kills two birds with one stone in that it functions as a seat and a lock, naturally making the former that much harder to steal. Its universal adaptor finds any standard bike and adjusts for your preferred seat angle. Once set up, pop it off the post, unfold its chain links, and secure Seatylock around a bike rack, your frame, and perhaps one wheel, space withstanding.
Find it at Kickstarter – $85