First, I just have to say these people saying "why do you need a gun if you live in a safe neighborhood" really aren't talking sense. This guy lived in one of the "safest" neighborhoods in America and got the pleasure of watching his wife and oldest daughter be raped before they (and his other daughter) were murdered in a home invasion. So you can totally discount what those people are saying (and don't listen to the "get a shotgun" comments).
Regarding the topic of which firearm to choose. Personally, I carry a Sig P220 .45. I would not suggest you purchase or carry anything other than a .38 .40 or .45 caliber. That is just my personal preference thinking that if you ever need to pull (if you pull you fire) then you want to put down the threat.
The considerations to keep in mind are: reliability, accuracy, ease of operation (shootability), carryability and affordability. You need to find a balance among those things to feel confident and comfortable if you do choose to carry.
So you may want to consider a Sig P239 (.357 or .40) or a much less expensive alternative S&W J-Frame .38 or a Kahr MK9.
Your first step should be to go to a gun shop and handle some of these weapons and ask questions of the staff. You need to see what fits your hands and get comfortable with the weight and feel of a pistol.
Finally, there is no harm in going through the process of getting the CCW but never carrying.