However if this is a career field you want to pursue then by all means go for it. 99% of the cops on the streets are great people who only want to do the job and make a difference. The media likes to focus on the 1%.
As Scott said above there are many different areas you can go into. As an officer I started on the streets, then I went to helicopters, mounted patrol, undercover narcotics, special events, community service and crime prevention and became a police instructor. When I got promoted to Sergeant I was in and supervised the following units, DWI, Radar, SOLO's (Motorcycles), Special Events (i.e, planned our PD's involvement and supervised personnel assigned to the Texaco Gran Prix, Houston Livestock Show & Rodeo, NFL Games, Superbowl's, and any other significant event that came up), SWAT (Supervisor), Bomb Squad, Anti-Terrorism Unit and Emergency Management. I had a very rewarding career and my abilities carried me where I went. It is a great job and the sky is the limit on where you can go, Chief of Police is always attainable. Just don't let anyone tell you that you cannot do it. If this is what you want go for it.