Dressing Up Can Hurt Your Chances of Getting the Job
On the other hand, many of my technical peers will consider you too uptight, if you show up wearing a suit and tie. If your suit is specially well fitted and you speak in an articulate manner, but are questionable in your technical speak, you may be seen as the salesman type (developers don't have much respect for the salesmen type). If the company that you are interviewing with, expects a laid back but proficient programmer, they may expect you to wear a polo and Khakies to the interview. Anything over that, may make you seem as if you are trying too hard to get the position, thereby lacking the confidence that you need as a developer, as demonstrated by not being yourself.
So the question is "how should you dress for the interview?" Dress up or or dress down? The answer to this question is: it depends. It depends if you are getting a job through your network or friends or not. If you are getting the job through your network of friends you should get the information from your friends. Ask what is preferable. In one case, where my job was coming a referral from a friend, my interview was a lunch at a sandwich shop. If you are going in cold, run it by the hiring human resources rep. you can ask the question as to what the interviewers prefer. Does that mean that you are not being yourself? Of course not, it simply means that you are willing to do those things that will assure you the success you need.
Frankly, most of the developer peers, who I have the utmost respect for, could care less about your matching pants and socks and more about your skills and your ability to articulate software development terms. The truth of the matter is that even to them, appearance is important. However, dressing up is not always the safer bet. On the flip side of that, is the sad reality that many hiring managers have no understanding of how to assess a good developer, and your apparel and other appearance is their main assessment.
To summarize, do your homework before you decide what to wear to that interview. Dressing up is not always the safer bet. Then again, if dressing up in suit and tie for the interview is a requirement, this can be a bad sign of what your new creative culture will be like.