Fitness equilibrium - what's your natural weight state?

After four months of focusing carefully on diet and training I believe I have reached my equilibrium point. Based upon my normal workout routines, nutrition choices and portion sizes I have stabilized my weight. Only if I consciously change my diet and/or increase the level of my routine will I further reduce my weight. Now the question is, "What do I really want?" According to the BMI calculators I am in the category of Normal. I have a friend who watches his diet and runs over 40 miles a week and his BMI score is Obese. He sure doesn’t look it.

I don't have the time to exercise more frequently but I can increase the intensity of my workouts and runs. I should probably do that anyway to increase strength and performance. I could eat less but why? If I eat the same and work out more intently will my weight go up because I'm building more muscle mass? If my weight does increase will I care? Is it worth thinking about everything you eat to maintain a weight that could not be achieved through a healthy diet and normal exercise?

I will benchmark this to see how things go over the next few months with no change in diet but a modest increase in workout effort. I really don’t care about my weight as long as my HDL, LDL, triglyceride and blood pressure levels are normal. Maybe it is time to buy that HRM watch.