Unless you're an experienced shooter, buy a Browning or Ruger 22 semiauto. you need a lot of range practice, 22s are cheap to shoot and you need a lot of practice.
I've never seen someone shoot a pistol well without help and practice. It's a huge mistake to get a 45, 40 9mm, or 357 right away.
I've seen a lot of people shoot, and few do it well unless someone has taught them.