I carry either of my Kimber full-size 1911's in a Galco "inside-out" IWB holster, works very well, very easy to conceal. I second the Don Hume, not bad stuff, plus they are very rigid in my experience, making them a bit faster draw than the Galco I wear, though not quite as comfortable.
Oh, and to answer the question, if you DON'T go with the .45, and instead go with .40 cal, I would get a used/factory re-certified SIG P226. The XD-45 is really nice, and a lot better capacity than SIG's single-stack P228, so if .45 is the caliber, I think the XD is a good choice. But if going with something smaller, I believe the double-stack P226 in 9MM or 40 to be generally superior to the XD in either...and you can usually get them for fairly comparable prices.