.380, back up only with well-selected ammo only
.38, with well selected ammo, can be an acceptable defensive round.
.357, excellent defensive round (my favorite is .125 grain Federals at 1,400 fps)
9mm, with well selected ammo can be an acceptable defensive round (I think the .40 caliber is better suited)
.40, very good primary round, select ammo carefully
10mm, an excellent round, but precious few weapons suited to CCW. The Glock 29 being the one exception I can think of. Significant recoil.
.41 magnum, powerful enough; not much of a selection of weapons for this round. Significant recoil
.44 special, a good primary round. The new Charter Arms Bulldog has gotten good reviews.
.44 magnum, powerful enough, but not much of a selection of weapons suitable for CCW for this round. Very significant recoil
.45 along with the .357 it is probably the most reliable man-stopping round. Use 185 to 230 gr. ammo loaded to +P if you weapon will allow. I've always found this round easy to shoot and there are a great many weapons available. This is probably my first choice for a defensive caliber.
.32 not sufficiently powerful
.25 not sufficiently powerful
.22 not sufficiently powerful
This is my take. But note even the .22 can stop and kill a man-sized mammal with a well-placed shot.
And even a .44 magnum can fail to stop a man if the shot placement is poor.
The 9mm's main attraction (as I see it) is the availability of cheap ammo.