@Harley:
The G23 would indeed be a good choice, the '27 for concealability (but somewhat snappier "felt" recoil due to smaller grip), and would complement your collection. Down the road, regardless of which one you get, you could purchase a barrel conversion and be able to shoot cheaper 9mm ammo thru it. Added flexibility of caliber.
Your choice of caliber is really your choice, your personal perference. A well-shot 9mm will outperform a poorly-shot .40SW or .45, so caliber should not be the single deciding factor in a gun purchase, except in your case it compliments your collection, simplifying your ammunition needs. What matters most is how well you can shoot it, and how comfortable you feel with that cartridge (I would imagine pretty comfortable, given your collection!). Cheers!
@MikeP: