I broke my official goals down into 10 lb. chunks. To help with motivation, I also have plotted what my reward for reaching each of those goals are, no time limit.
I have those in a little chart posted on my wall to fill in as I achieve them.
I also have my unofficial goals, which have actually proven a bit more motivating. I started at 202, getting into the 190's wasn't too hard, but from then, another motivation has been to get into the 180's and now into the 170's, and so on.
Another unofficial goal is to be able to buy smaller clothing sizes. My sight is now set on size 12 (who knows when I will get there).
Basically, you can pick whatever it is that matters to you (clothing, being able to do an activity, 5 lbs. at a time, etc). I find that having it written down somewhere where I can look at it helps a lot too.
(As I said, one is on the wall, but on the fridge I have a board with the goal of wanting to get to the 170's).