My fiance isn't fond of the idea w/one in the chamber in the nightstand. Full mag inserted, not racked. Full spare sitting right next to it. I don't see an issue w/racking it - takes practically no time at all.
Kerby - surprised no one mentioned for you - there's a bit of a risk with one chambered on your shotgun. Most, if not all, are not "drop safe" like most semi-auto's now'days are. It's best to have a full mag, not chambered, and (imo), safety off. I have an 870 that sits "cruiser ready" - with a cleared gun, close the chamber, pull the trigger, then load the mag tube. Now all you have to do is pump (and not manipulate the little lever to open the action) and go. Just my .02.