I've used a tripod maybe twice in my life. I own a pretty nice one too. Flash? I've used one once or twice. Don't even own one anymore. Tripod and flash is too much crap to lug around, especially when I just want to carry one lens, one camera, and go. Personally, if I only worried about ultimate sharpness I wouldn't shoot with a 40 year old lens wide open at f/1.2. I sure as hell wouldn't shoot it at 1/8-1/15s either. These aren't sharp pictures, they're usable pictures. Sometimes, thats all that matters. Besides, when I'm shooting at such slow speeds, I'm usually in bars, or some band is playing, etc. Tripods and flash don't go over too well in those environments.
If I wanted to lug out a camera and take pictures of mountains and clouds and deer I would use a tripod, but thats not my style (no offense to anyone who likes those types of photos).
I'm not attacking the "use a tripod" people, but we all know what we were taught in Introduction to B&W Photography. I don't believe we need that info rehashed to us. However, most of us, I believe, have realized what we like and the type of photographs we want to take. If that means not using a tripod or flash, then whats the harm in that?