when you consider a CCW firearm also consider the type and availability of holsters available for any model of handgun you consider. Overall, this should not be an issue except it seems like every LGS in my area carries a decent holster for a glock, but not for the 1911 that I carry. Anyways make certain you can find a quality holster that works for you. I have a motto; buy a guy buy a holster, they are not complete without each other.
IMO, I would pick a 9mm over a 40 for any smaller compact pistol. I agree about single stacks being easier to conceal.
lightweight, cheap, strong... pick 2