Normaly I wear a button up or a polo from American Eagle or A&F with a pair of jeans or khakis. Senioritis has set in though and I usually go to school in a pair of warm-ups or something. I don't care anymore.
I just stick to simple, no companies in particular. I'm a runner so I have some running clothes. For school I have a dress code so the only time I change from that is on weekends.