My official goal weght (chosen by me) has always been 140. It's what I weighed when I was in my 20's, twenty years ago. I've been at goal around 3 years now. I'm actually 5 pounds under goal and am thinking about losing another 5. Your body may decide when it's done losing. Also, you will have to decide how much work you want to put into getting lower. I think I could easily maintain about 15 pounds higher if I didn't work hard at staying where I am, but I like being this size.

The smallest I've ever gotten into in my teens was an 11 at 160lbs. My current goal is to get back to 160 even if I'm not in an 11 at that point. Once I get there, I'll decide what I want to do, but it's definitely normal (and I think healthy) to reassess your goals at different intervals.

I started at 275 wearing 22s & 24s. My goal was to be a size 14 and weigh 165. I am 9 months post op and I am a size 8 and weigh 149. I have never been this size before, but, I like it. My goals have certainly changed. I am working to stay this size. There is still the daily goal of getting in my protein, water, and vitamins.

It really helps me to make a lot of mini goals with mini rewards for reaching them. For big milestones (like 100 lbs down), I have bigger rewards. I keep all my info on a nice spreadsheet and keep track of everything (all my goals/rewards, dates I met them, etc).

My first goal was to lose 30 lbs, and I rewarded myself with a new scale. My next was at the 50 lbs loss mark at which point I bought some new hair accessories. My current BMI is 42, which is considered morbidly obese. My next goal is to have a BMI less than 40 so that I am just obese. This will happen in 12 lbs. At this time, I'll buy myself some new nail polish.
Other goals are fitting into jeans that are not in the 20s, getting to onderland, BMI<30 (just overweight), etc.
Also, because weight/pants size/BMI aren't everything, I have objectives and rewards for meeting those objectives for times that I know are going to be difficult to stay on top of exercise and eating well like the first week of classes (I want to start my gym routine right away without slacking off), halloween, thanksgiving, christmas break, and new years eve. For me, I know I'll be tempted to go lighter on my exercising and to maybe have bites of bad things, but facing those problems and allowing myself a reward for meeting those (new outfit/shoes/manicure/pedicure/etc), I find it is easier to stay focused.
I also put away $3 for every pound I lose so that once I have reached a goal weight and maintained it for a few months, I'll allow myself to use the money to buy a new wardrobe.