Originally Posted by ter1413
A suit is not appropriate for every job interview. If you showed up wearing a suit for an interview to be a lumberjack it would be akin to wearing sandals. Either outfit would get you laughed off the job site. That is an extreme example but it illustrates the importance of dressing for the job.This article
is a little old but still has some good reference information.
People sometimes wonder how they should dress. The most important thing is that you feel comfortable. If you still want a recommendation, I say a button-down shirt or even a T-shirt. A suit can come off as too formal in some companies (e.g. Google).
This point is not as important, because people won't really care. You should ask your recruiter about what to wear, since this differs by country and East Coast / West Coast. A company like Google is more casual, so if you come in a three-piece suit, your interviewers may raise an eyebrow. If you've got the goods in terms of engineering skills, it's not a dealbreaker though. One candidate came to an interview wearing a gothic mesh shirt with holes through which his nipples were clearly visible. He still got the job. (I don't recommend taking this risk.)
Niniane Wang (author) was the engineering manager for Google at the time.
Living in New York it is definitely going to be a little more formal than here in the Bay Area. I'm not saying don't wear a suit, just trying to help you make a more informed decision.