As was mentioned... all the common handgun rounds will penetrate walls and can pass through the body of an attacker. Using hollow points helps prevent pass through of a person, but they do not prevent penetration of walls should you miss.
As was said... consider and plan what you would do in an emergency situation.
All the major calibers perform similarly in tests when using quality HP ammo, do do not worry about effectiveness of different calibers too much.
Gun design/shape, weight... they have a big effect on felt recoil. A 45 in a heavy 1911 is not too bad, but in a small light poly gun... it can be a handful... 9mm is light shooting, but can get snappy as the size and weight shrinks.
Also... handle and shoot any pistols you think you are interested in... this was mentioned above.
My biased opinion... CZ 75b... I have two, and I love them.
For a new shooter, the decocker version (CZ 75DB) would be my choice... unless they can count on an experienced shooter's assistance with training and learning... or at least are dedicated to educating themselves and training.
Last edited by marine6680; October 3, 2012 at 06:00 PM.