What do you think my goal weight should be?

Really it's what you feel comfortable with (:
The 'Healthy' range is 115 - 154, which is quite a wide gap.

I'm 5'6" and hovering around 140 now. Pretty comfortable with all my muscle but would be satisfied around 135. I sat at 150 for several years and I can't believe the difference in only 10 lbs.

Seriously you have already gotten some good advice, within the normal weight standards for you age height and body build. It is all up to you.

I have seen the weight management people at the VA Hospital who told me my goal should be to lose 10 percent of my total body weight. I was at 287 so at 6'0" they set my goal weight to be a ridiculous 258.Another doctor I see set me a goal of 250 and a third at 235. ALL of those are still obese. I told them all that that would still put me over weight and my goal was not to lose weight to still be over weight. I lost, in three months to 219 and am still far from done. I am shooting for 182 which is within normal weight limits for my age/height.

I wish you luck, you are a smart young lady.