Why not set a goal of 150 and see how you feel when you get there?

I'm 5'8", medium build, and am shooting for 155 right now. Then I will assess the situation. At 167, I wear a size 10 (was size 18 at 215) and look pretty good. Just have some extra fat to lose around my middle and hips/thighs. Much lower than 150 and I think I'd start to look sick.

You can't really compare yourself to anyone else. Everyone is built differently.

I personally think setting a reasonable goal is best for staying motivated. You can always lower it later.
Good luck to you!