I once read somewhere in a job or human resources article that you are supposed to dress for the job that you want and not for the job that you have and I agree wholeheartedly with that statement. You should dress for the position that you want even if you are just an entry level worker who aspires to be Gordon Gekko or some hotshot banker/lawyer.
Besides on job interviews, in my seven plus years of working professionally, I've never had to wear a tie to work. I've always liked that I could wear whatever I wanted to work. As long as I don't wear a t shirt, shorts, or sandals to work I know that I won't have a problem with HR. I normally wear a collared shirt, jeans, and sneakers to work and for the most part I've been happy.
The job that I have, which is essentially in a call center, doesn't require any formal business wear. Recently, however, I've discover that I tend to be more productive at work when I wear formal business attire. I just feel better about myself and my job. You know what's funny though when I was in catholic school I wore a a tie everyday to class!