Wait lists also could depend on your particular field of study, too. For example, I'm wait listed at Texas Tech, and when I emailed them, they said I am the next person in line for the British Literature pre-1700 field. Whether or not I'm accepted will partly (or completely) depend on whether the person in that subfield declines their offer. The DGS also said that in normal years, they admit 50% more students than they have funding for (they fund everyone) expecting some to not accept, but because of the tough economy, they can only admit the number they can fund this year (which is 5). They put 5 people on their wait list (4 others and me), but I'm not sure if those 5 people represent different subfields or not. He didn't say.
This waiting sucks.