A gun will get you in trouble in your home, on an airplane, and especially in the street. If you don't get shot yourself, just add an extra 25 years to your sentence for using a firearm in commission of whatever felony the end up getting you on. While you wouldn't want to bring a knife to a gun fight, a knife may be a better choice for personal protection. Because at least you don't have to worry about incurring firearms violations, yet it can be just as deadly.
That's why I love the state of Indiana. I carry a pistol with me daily. If I'm ever forced to use it the law is on my side.
In terms of fights going to the ground. I have a feeling that the popularity of MMA is going to cause most 'thugs' to start to adapt mock styles of MMA fighting. They see it as cool and powerful and will emulate it. I've seen this happen in my real life. I ran a small mma club at a college and we would get all kinds of 'street fighters' who wanted to train. They had watched TUF and emulated the lingo and style of what was seen there. While some were tough, all did not have real training, but none the less they still attempted double legs, chokes and armbars. Also, in this area wrestling is very popular. So many of this new breed of kid is all about using wrestling to sit on your chest and pound your face in.
The truth though is that I'm in my 30's now. They only fist fight I'm going to get into is on the mat. In 'real life' if it reaches that point I'm in fear for my life and several things have gone really wrong. And that is why I carry a firearm.