Here's the best advice you will get:
PICK 5 SCHOOL'S on test day, regardless if you know where you want to go or not. You should pick the 5 most likely schools you'd like to attend. The reason for this is that those 5 choices are FREE on test day, but will cost you money per school anytime after test day. You will make you choices before the test, on your computer. These schools will not be sent official reports, instead they will only be granted access to your official reports. Sooooo if you end up applying they will have access, if you don't end up applying they will never take a look. It's as easy as that. Pick 5 schools on test day. If you don't pick 5 schools then you are wasting a free opportunity to make your score reports available to the schools you might attend.
There is absolutely no disadvantage to picking schools for this. And if you end up having to take the GMAT again, you can list those schools again.
I plan on only applying to 1 school? WHO CARES, PICK 5 SCHOOLS
I might take the test again... WHO CARES, PICK 5 SCHOOLS
But I'll just send them later... PICK 5 SCHOOLS, ITS FREE WHEN YOU TAKE YOUR TEST
I don't know where I want to go... PICK 5 SCHOOLS ANYWAYS, YOU PROBABLY HAVE 5 IN MIND YOU MIGHT ATTEND
Get the gist?
GOOD LUCK