RE: .38sp vs 9mm vs .45ACP
One other thing to consider about the Glock 20/21 is that they are large, full frame service pistols. If you want a gun for CCW, the 20/21 probably isn't it. But as a nightstand gun they are great. I would really like to get a tactical light/LAM for mine. It also needs a set of night sights.
Mike