Frustrated but not disappointed

Here is the issue in a nutshell, and I have read enough of these posts to know that its ok, but that f&*#in scale has not moved in almost 3 weeks. And I'm not really sure why.
I have been busting my *kitten* at the gym or doing something at home (running or biking) to the tune of about 600 cals burned a day if not more. That number is taken from my HRM, if Im at the gym and the equipment says less, I use that one instead.
I'm also doing a bunch of different things, changing things up a lot so I don't get bored.
That being said, I weight/measure just about everything that I put in my mouth. I am just about always under my daily calorie goal. I know a lot of people say to eat their workout calories, but I am honestly just not that hungry.


I say frustrated but not disappointed b/c overall I have seen a change. My Body fat % has gone from 26% to 21%, I have almost doubled my weighs I use in the BP classes since I started. I can bang out 100 pushups in about 2 mins, I can run for 30 mins straight at a 10 min mile pace and and yes my clothes are loose on me, but I am stuck at this stupid 200lb # and I can't seem to break it. And its just pissing me off. I start my Ironman training May 1st and I really want to be at that 180ish mark when I start.

One thing that I don't do is lift (freeweights). Its one thing that I honestly do not enjoy. But if working that into my routine would make a different, I will do it.

I am up for any suggestions, feel free to peak at my diary, I am open to any suggestions/criticisms (trust me you wont hurt my feelings) that could help.

Thanks
-Rob