I'd grab whatever was close at hand and ready.
Most of my longguns are kept in a storage unit away from home so I guess it would probably be my Marlin Model 60. I wouldn't have a problem w/ .22lr but I probably would prefer something quicker than the tube mag. I'll be bringing the SKS into the house as well and that w/ some stripper clips would be fine. In both cases I can think of others that may be more ideal but either would be more than fine.
For handguns, I guess whichever came to hand first or whichever I had set up for home defense at the time. Probably my S&W 65LS, 6" S&W 586, CZ 75B or Charles Daly 1911 (they alternate HD duties, though it is usually the 65LS). I'd probably take an extra moment to set up my Bersa Thunder to drop in my front pocket as backup. I'd be perfectly happy with any of them.
Then again, if I was in a hurry why would I pick and choose. How about taking the one set up for HD (one of the above) plus one of the two bags I always have ready (between the two they hold all my handguns except the blackpowder revolver and the 6" S&W 586 since one is not very usable for anything but recreation and the other is too big, the bags hold ammo for the guns in them, holsters, and cleaning supplies).
I understand that the scenario wants only one, but why would I want to take extra time to drop to one when it would take less time for me to grab a bag full of guns and supplies?
(I guess that means I'd go w/ the handguns over the long guns, unless the situation that caused me to run clearly called for a long gun)