Really interesting post, I've had the military background, wrestling, rugby, amatuer powerlifting, and more bar fights then I should of been in. I live in vegas and because of my job I run into alot, ALOT of MMA/UFC wannabe's, guys who enroll in a gym and wear some TAPOUT gear puffing out their chests. Don't get my wrong true fighters deal out some major damage, those boys who actually fight in fights not just spar, but thats maybe 1% of the population.
I say stick with what DFW1911 says, "soft" styles, grappling, submissions, takedowns, almost all fights, street or professional, barbrawl or school yard scuffle ends up on the ground. Strikes, punches and blows and kicks are effective but you gotta be REALLY lucky to end it with that or train for years to be able to use it proficently in spur of the moment dirty fight.
Forget what these other guys say about not packing on muscle, I'm 6' 250 lbs, fast and have taken out small quicke trained guys and the big ole meathead boys too. Muscle doesn't slow you down, only thing it does is give you an advantage. I've gone to the gym and sparred with my boys, they got speed yes, but if you got some solid size you can take a hit (and yes I have, bruises the size of basketballs on my ribs, legs and face) you can easily overpower them if you know some basics. Superior strength can resist alot of armbars or other locks just because they do not have the strength to put it in, although if they do your screwed. I have some massive legs that are very strong, this is a huge advantage for me, it aids in keeping you balance when someone attempts to take you down, provides huge power in a throw or defending against a throw, for me personally it allows me to easily lift my attacker off the floor (there have been situations where I had to deal with REAL fighters with the knockout punch and just holding them there basicly gets them flustered, can't afford new teeth!) and the added mass absorbs a strong kick, that wall of muscle can really take a beating, tho pretty sore for a week or 2 afterwards.
Any real street fight takes a 30 to maybe 2 minutes max, realisticly if you train stick with takedowns and submissions. No body spars like in movies or tv, anything longer than 5 minutes is just puffing your chest and usually someone calls the cops. Judo, brazilian ju-jistsu, Russian sambo or systema (which you should really check out, quick, realistic applications) are probably the best. I'm not knocking the muay thai or karate guys, I KNOW that they got those lights out blows, but the Dr 2 B probably does not have the time or the dedication to be able to master those disciplines. Armbars and doubleleg takedowns are quickly learned and besides in the realworld where everyone is sue happy, its better to breaksomeones arm who "came at you" then breaking their jaw with a punch. He came at me and I just defending myself...hint hint.
For jon in wv, not knocking you, but out here 183 is average, 230 and up is bigger and then it just goes up. If 183 is big for you then I have to assume you were much lighter pre-weights so therefore not a very reliable source of "fat" vs "muscle" arguemnet. I used to be fat at 265 but now a solid and even thicker 250, and I can assuradly say muscle is definitly more protective then fat in absorbing blows. I got 23" arms and 13" forearms, it provides me with a stong grip and my opponents cannot easily break out or manuever my arms when I'm grappling with them. I also do heavy training on my shoulders and neck, hat/w chains and weights up to 135 lb neck curles so it's thick and solid; saved my skin. I got into a arguement with a big ole boy who used to play semi pro ball and trained muay thai, literally round house kicked me from 6 feet away left a shoe imprint and one ****ed up nose on my face, but I was standing solid cuz my neck absorbed alot of the impact. Weights for size and strenght help. Not bragging or slamming, I'm just sick of people saying its not effective, look at Brock Lesnar, going against Couture who has over a decade more experience then him was basicly rocked because of sheer size and strength, that boy is not slow either, his size is not limiting his mobility or speed. Don't discount muscle if that isn't your choice of form. I can't do TKD much less compete, but a fight is something different, gotta have any advantage you can get.
Even if you are carrying having the personal knowledge that you have another backup defense to your primary defense, it's invaluable, and a real boost in confidence.
Besides if you have size that usually prevents a fight anyways, who wants to fight a big guy?
For proof I am on the Right: