I carry a folding knife. It has a 5.2" blade. I literally carry it every day. It's not even a bother. Here's a link.
10100 Details | Benchmade check it out, it's a kickass knife.
I also carry a smith .40 cal (loaded with JHPs), and, depending on where I'm going, an asp. I always have an asp in my car.
I actually carry a blade that size as more of a deterrent than anything, especially if I don't have my asp. If I have my asp on me, its definitely my first choice if its a non lethal situation (jumped by a few attackers) If it was lot of people, I'd open fire. You're legally justified in that situation. Call me hard headed, but I'm not taking an ass kicking to give some pricks my shit. I also carry to defend my girl, and any innocent people in danger that I would happen to cross paths with. I'd step into the middle of an altercation to protect someone I knew was innocent.
Yes, Deterrent. If it was two guys on me, I'd pull it out... if it didn't deter them, I wouldn't have a problem trying to hit some non vital areas. Just inflict pain and hopefully get away. I don't get joy out of causing others pain, but I'm not going to lay down either. If it was a situation requiring lethal force I wouldn't even mess with my knife, my pistol would be out.
Fortunately I've never had to use any of it. I've never even been in a
serious fight. I don't go around looking for trouble and do my best to avoid it.
If you don't wanna carry, that's your right. You can go on all you want about how its not necessary. But, I'd be willing to bet when the shit goes down, you'll want a trained, law abiding citizen around who just happens to be packing more than his fists.