Totally agree. One more thing I'd add is: tell your candidates up front what to expect of the process. An overview after first contact is nice, but interview-day schedules specifically seem to help alleviate the jitters. We've started giving candidates a schedule with names and rough content before they arrive: 10a-11a - pair programming on a TI Launchpad with Jerry; 11a-12p - planning and organization exercise with Sam; 12p - group lunch; etc.