I know I am not maintaining (I'm bored so wandering threads I don't normally read lol) but I think that 150-155 is a good buffer, it depends on what your water weight gain tends to be. Or if you don't make it to 150 maybe 153-158.
My water weight gain can be anywhere from 5-7 lbs if eating pizza or mexican so I personally may give myself a slightly higher buffer OR not count weigh-ins the first day or two after eating out.
I've been maintaining for about 3 weeks I think and I've managed to stay between 152-154. Next week I go on vacation and am comfortable with a bit of a gain, knowing that I'll have to come home and lose it again.
Started - 12/25/11 at 265 lbs.
ONEderland - 2/16/13 at 199 lbs.
Goal - Normal BMI! - 7/17/13 at 155 lbs.
Refocus - 1/29/15 - 185 lbs.
Oooh your stats are a lot like mine, 5'6" and around 155 ish, i'm a couple lbs heavier than you are i think, i have a very crappy scale but i weight just about every day and i'll start sweating bullets if i get over 160.
I think 5 lbs is a good buffer especially if you factor in water weight, etc. but i wouldn't feel comfortable personally with more than that (i'm newly maintaining for about 6 months)