The reason schools are a good place, is because they are a place to start. Yes, they wouldn't necessarily be an all you can eat buffet, but they'd be close. Teenagers are much more emotionally fragile, think that every minor thing is the "End Of Their World" and react accordingly. A handful of whampires would find great feeding there, and more importantly, be able to set patterns of behavior in many kids before they fully cement their behavior. They'd be creating new generations of prey more susceptible to influence.
Malls are typically filled with those same kids, and generally filled with their share of mall-rats (who would be good meals). And it depends on the mall. The one close to me, is highly teen-centric. And you should see the looks of disgust that a lot of the adults have. A good feeding place for lust too.
Sports complex would definitely be a good place, which reminds me: Bars. Why do a lot of people go to them? Because they're desperate/lonely/insert negative emotion here.
Not to mention, any big office building would probably be a cesspool of despair and hopelessness. It's not called the "Daily Grind" for nothing.