Wow. It's good to know that there's light at the end of the tunnel. I'm down about 80 pounds myself right now, and have probably 60ish more to go. It's nice to know that at some point you can cross the line from "you look good for someone who was so big" to just plain "you look good".
For anyone who is serious about losing a bunch of weight by counting calories, I recommend you really be religious about logging everything into a food tracker of some sort (I use http://sparkpeople.com
), even if you know that you blew it for a particular day. It takes a lot of discipline if you're seriously in it for the long haul, and you can't let one bad day here or there kill you.
FWIW, I target 1200-1500 calories a day (yes, that is insanely low, but I started at about 300 lbs and needed to go hardcore). I make sure I eat at least 80-100 grams of protein a day. You need to increase your protein intake a bit since your body will start burning more protein for its caloric content, leaving less for rebuilding lean body mass.
Sounds reasonable! 1800 calories is apparently what I need. How long did it take you?
The rule of thumb is that 2000 calories is roughly equal to 1 lb. So I think 5-10 pounds a month is a good estimate, and that pretty much matches my experience as well. The first month's weight loss should be significantly higher, too.