I carry either an 4" XD in .40 or a SA 1911 Champion Commander, in .45 of course. But seeing as how this thread was titled Glock or XD, I voted for .40
4" XD 45 Compact, Trijicon night sights... Comp-Tac CTAC holster, but if I dig the Crossbreed I ordered for my wife's sub compact XD9, I'll end up selling the CTAC and getting a CBST for myself...
For duty I carry a G17 unmodified except the sights. Trijicon night sights. Im not sure why some people find themselves having an overwhelming need to modify a Glock. Either cosmetically or mechanically. It really dosent need anything.