Well, I am the odd man out on this topic; I voluntarily wear a tie and sport coat to work every day. Now, I don't mind that other people prefer more casual attire at all. But for me, I feel... more work-oriented when I wear shirt and tie. It has taken on a sort of "uniform" aspect for me, and it helps me establish that separation between "work mode" and "personal mode".
I will say, however, that I do believe some places have gotten somewhat out of hand. While I don't believe you have to wear a tie to act or be treated professionally, I generally don't want to see your underwear hanging out. And holes in your clothes? Unless you're doing something physical, or you come in after hours, holes are just something that don't need to be there.
Now get off my lawn.