2 lbs is totally sustainable. I lost 80 lbs this way and have kept it off for two years.

I would say 10 lbs a month is about average for someone who is motivated and losing weight.

I have to disagree. Most doctors will agree that losing up to two pounds per week for a healthy adult is acceptable and normal during the course of intensive exercise.

Much like matwood, I was ~205 at 6' with an athletic build. I wasn't overly fat, but hefty (ok, kinda fat). Running and working out six mornings/week and basketball in the evenings allowed me to drop 2 lbs/week, to a much leaner 165. Coincidentally, I had a doctor visit or two during that time and the doctors never expressed any concern over it.

Fortunately, and I believe this generally for healthy adults, you will reach a plateau. I did so at 165 and never fell below that, even when I increased my running, lifting and other recreational activity.

You can't sustain any weight loss no matter how little for the simple mathematical reason that body weight is nonnegative. I do agree that 2 lbs/week which is about 8000 calories, or about 3-4 days worth of calories, is a lot. For an average weight person. If you weigh a lot then it may be ok because you naturally burn more calories per day so 8000 calories may only be 2-3 days worth. You shouldn't look at the lbs/week figure but at how many percent fewer calories you're consuming than you need to sustain body weight.

At some point though you shouldn't want to lose anymore weight. Unless you start out really overweight, simply losing weight shouldn't be the goal anyways. Lowering BF% is a much better goal that reflects your overall body composition. I'm 6' 1" and almost 200lbs and weight wise I could be considered overweight, but my BF% was 11% the last time I had it checked and I've since gotten leaner.

In short, don't get depressed about the scale. Look in the mirror and keep making body composition changes.