A Glock 27 or a Smith & Wesson "Shorty .40". Both are excellent with great safety features. If you want something small get a S&W titanium .38, and use +P rounds.
I actually have several weapons, and my carry choice is a Colt .380 SA on most occasions simply because it is much easier to conceal, but the Taurus titanium .357 goes in my fanny pack when I wear one.
My personal choices for home defense are 1 UZI 2 AK47, but I understand that other people are more comfortable with other things.