I'm a recruiter, and I recently had a candidate show up to an interview for a very hands-on, mechanically oriented position wearing a suit. The hiring manager thought that was great; it made him stand out and showed his professionalism.
I used to wear a suit to work when many of my colleagues dressed business casual. They would rib me about it and ask me why I dressed up so much. My answer: If I'm the only one in the room wearing a suit, it still only takes me about thirty seconds to convince people that I grew up in a small town and have done my fair share of ditch digging and fence post pounding. On the other hand, if I'm the only one not wearing a suit, it is a much tougher up hill climb to get on the same level.