Just got myself a new quick release rear wheel. Fantastic, right? Well, it's sort of a pain because I'm always worried it's going to get nicked. Usually, I just take off the front one and thread the lock through both wheels and the frame, but in unusual situations (eg When locking up two bikes with my one lock) it's necessary to remove the rear wheel. When I put it back on, I worry that I haven't centered it absolutely perfectly, and that I'm going to destroy it by riding it like that.
So, question: how can quickly be sure that I've centered by wheel, other than by just 'eye-balling' it?
EDIT AUG 3 2011
So thanks for the answers, but a lot of people are addressing how to safely lock a bike. I appreciate that, but my question (italicized above) is regarding centering a wheel. There are other reasons to take off both wheels, like if I need to fit the bike in a car. Thanks again, everyone, because it's also helpful to have tips on how not get your bike stolen.