I don't think it matters. If you have it on a tac sling, like one of these www.cqbsolutions.com then I think the drill is to just let go of the carbine and draw and fire two handed if you need to transition to your pistol because you have a stoppage or are out of ammo.

Most people I have met off this website carry Glocks or 1911s, although we bicker about it constantly get whichever you like better, though personally I would get a 1911 from one of the "name" manufacturers and & like any pistol, run a significant amount of both FMJ and carry ammo through it to make sure it is reliable before carrying it. I still think you are more likely to get a klunker that needs to go back more often with 1911s than with other pistols, whether Glocks, or DA/SA pistols.

I guess the next most frequent is Sigs, particularly the 220.

Almost everyone seems to own a Beretta 92, but nobody seems to carry them. There have been complaints about the Beretta mags crapping out with the sand in Iraq, I wouldn't know as they work in the snow.

Do you already own a pistol?

editted to add-Browning Hi-powers are nice pistols also.