I think the right answer is Glock 17 but I voted Glock 19 because it's a compact and renders itself to concealed carry a little more easily. Since you didn't give a purpose in your OP, I'm assuming all purposes.
If you're not a liberal when you're 20, you have no heart. If you're not a conservative when you're 40, you have no head.
- adapted from Francois Guisot (often wrongly attributed to Winston Churchill)