My self image tends to be all over the place. I'm pretty tall (6'5") and for a good while, I tipped the scales at a whopping 165lbs. I'm now around 180lbs, and generally happy with how I look, but I still hate my hair most of the time, and I have a perpetual fear (bordering on paranoid obsession) about getting a gut as I get older.
All the guys in my family are tall-ish, and all of them (my Dad through my uncles) have the guy-looking-preggers gut. My whole life, I've been told that my metabolism will only last until I'm 30. So I obsess. The problem is, I don't do enough to combat it, so as with most people and self image stuff, I'm my own worst enemy. The thing is, I've got a 32" waist, and there's no reason I should be be this worried about something I can prevent. I guess having had crappy self-esteem all through high school and most of college just made it harder. I've dealt with most of the residual crap, but I get these odd surges of near-loathing or self-pity for no reason.
Anyway, I generally like my looks and my body. They always could be better, but I try to be content because I really have no reason to not be. Plus, if things go south and I get fat and sloppy, I really only have myself to blame. I can (reasonably) control my diet and my lifestyle, so if I'm not happy with how I look, I need to do something about it. If I don't do anything about it, I must be pretty comfortable with it.