@Andy Bottomley
Andy, As a contractor i would like to say my experience, with regards to worthless work-shy collogues is the exact opposite to your own, however I tend to find that you get work shy permanent and contract staff. The only difference tends to be that the contracting staff get the punt in short order (if the organisation has a clue).
As for highly valued integrity believe it or not i suspect a large percentage of contractors, trade on professionalism and highly valued integrity, but we are also commercial business, something that is lost on most permanent staff, in short we do take the good and the bad days and mostly get the job done to a high standard (if allowed).