The company I currently work for uses a two-step interview process for both consultants and GIS/DBMS developers. First, the hiring supervisor will have a screening interview by phone or in person of app. 1 hour. This is to review the resume, get afeel for real relevance of experience to our work, and otherwise decide if this person is worth pursuing.

Success in this interview will lead to an invitation to an on-site series of interviews, which collectively will take 4 - 6 hours. Lunch is(of course) part of the interview process. Meetings are app. 1 hour each and will be with the supervisor, one or more project managers, and one or more technical staff (and possibly VP or above) -- tailored to individual skill set and anticipated duties.

We use more problem-solving and management oriented scenarios in lieu of the coding tests described. I like questions like the "beer container", which have no single correct answer but let the interviewee show how they work through a problem and how they present their answer.

The lengthy interview & mix of one-on-one and panel formats gives a good idea of how the person will work in front of clients. It also gives them a variety of opportunities to impress -- since some folk do better in one venue than another.