i would def. not have the surgery during the semester. i was miserable (and so out of it thanks to the liquid pain meds) for the first week after that i could have never imagined trying to walk the hills on my campus. some people say "it's not that bad," but i will be the first to admit that i am a major whimp. still, at the age of 21, if i am sick i curl up in my mom's lap and make her scratch my back, rub my ears, and do all those things moms do when we are younger (or now, since we live in different towns, i just call her and cry).
if you insist on having it before christmas, i would say thanksgiving would be best. but you also must think that as soon as you get back from thanksgiving break you will have finals to worry about. a new band packed on top of all the stress of studying (and you won't have tons of energy, for awhile atleast, to study b/c of the liquid diet) might cause problems for you grades and health.
i had my surgery the day after christmas. it sucked having to watch everyone eat christmas dinner while i retreated to my room with my slim fast, but after it was over, i was so happy i waited. since i had my surgery in my hometown (which is 200 miles away from where i go to school), and the fact that i had so many dr. appts leading up to the surgery, my boss just gave me the whole month off. by time i got back to school i had lost a bit of weight, gained tons of energy (thanks to the lost weight & massive amounts of sleep), and was ready to face a new semester.