Do I dress nice for second interview?

This interview is at my office. No, seriously. The second interview, for me, was with the directors, though it may be different for IT folks. I recommend the suit, you can't go wrong; though this is a casual office people will be impressed by your professionalism. And I won't pass on the fact that you may not accept the job if offered...

You've seen the place and the environment...if you go there entirely overdressed, you might be demonstrating that you didn't pick up on or 'get' the culture there. You have more information than the last time you were there. I'd match them, but picked up one notch. Show them you learned something about their culture and you are applying it, while still maintaining that you mean business and are dressing to impress.

Dress for the job you want, not the job you have. I'd wear the suit. Terrible advice. If these IT guys have any say at all, they will pick the guy they gel with who has the knowledge. I work in an IT department and we wear business casual. If someone came in for the first and 2nd interview wearing the most formal clothes possible, we would laugh at them as soon as they left.

I am a programmer, and I interviewed someone wearing a suit and tie yesterday. I was wearing jeans and a t-shirt I just spilled coffee on. Clothes did not concern me a bit; the answers to the questions were what I was focused on. Basically, you never know what to expect for an interview, and dressing up isn't going to hurt you. I couldn't care less what you wear to the interview, as long as you are clean. "Dress for the job you want, not the job you have" is bullshit. What does that even mean in the context of working with computers? Computers do not care what you look like. I treat work like home; I sit there for many hours a day; thinking, typing, chatting; and I dress for that. Comfortable. (I also wear clean socks so that nobody cares if I walk around the office barefoot.) Thinking, not appearing, is what's important. So dress for that. But I agree, a suit and tie isn't going to count against you. Jeans and t-shirt or business casual also isn't going to count against you. Wear clothes. That's all that matters. (And oh yeah, this is no silicon valley startup. It's an investment bank with 250,000+ employees. So you might even be able to call this "the real world".)

Nthing the suit. You don't know if someone else is going to be interviewing you or whether some higher up is going to pop in to put a face to the name. You're going to want to make the best possible first impression if the need comes up. It would kind of be inconvenient to dress back in business clothes as I will be leaving my current job for the second interview. The issue is whether or not a particular set of clothes makes a better impression. Would you ever tell an interviewer you didn't wear a suit because you didn't want to be inconvenienced? Hell no. Don't include this as a factor in making your decision.

I'm in software, and in San Francisco, so I never wear a suit to work, and neither does anyone else. If someone showed up to an interview in a suit, I'd (uncharitably) wonder what he was trying to hide. If I had an interview I'd dress like I would for a first date. But I also recognise that lawyers have a different dress code, and out there in the east I hear everyone wears a suit.

If you want to wear a suit and can't leave work in a suit. Just keep your suit in the car. Leave work, stop at a fast food joint with a decent restroom/bathroom, change there and head to the interview. Change again on the way back to work at another fast food place preferably. If you feel guilty about using the place to change, buy a drink. No biggie.

It may also depend on who is interviewing you. Lawyers tend to like suits.

I'd go with my nicest (not most fancy) business casual outfit, if I hadn't just seen someone who works there recommend the suit. It's not just that IT folks don't value the suit -- they (we) sometimes look down on people for wearing it. I have a very negative visceral reaction, for example, to opinions like: Dress for the job you want, not the job you have. I'd wear the suit. People in the job he wants don't wear suits. But, having seen what someone who works there recommends, I'd go with that recommendation.