When I first started, I consistantly lost 1.5-2lbs every single week. I wasn't even trying very hard, I probably ate 1200-1800cal/day but I didn't record, and I didn't exercise at all. Then I plateaued at 150lbs and stayed there for a month. I had to totally revamp my plan and get a lot more nitpicky. I now do an hour of cardio 4 times/week and 30 min of strength 3 times/week. I also measure food and count calories and stay between 1200-1600. I no longer lose consistantly. I'll drop .5lb/week for two weeks, then nothing for a week, then have a 2-3lb drop the week of my TOM. I've done this for two months now.
So anyways, have you noticed any observable patterns? Is your weight loss fairly linear or do you plateau and whoosh? Has it changed at all as you progress?