First, I agree entirely, "Just say NO" when a spec is doomed to failure, or is against your principles, or is just plain a bad thing (tm). I've worked mostly as a contractor and I have lost one or two bids by saying NO, but the bids that I got even when I did say NO were the best gigs I had - an employer who says "hmm, this guy has the guts to say NO, maybe he knows something I don't" is a good employer.

From the contractor's perspective, I've most often seen this combo - 1) the MIS department which takes the big picture only in so far as the entire goal is stability, lack of change, and lack of users bugging them 2) various web weenies who like making cool effects but have no concept of how what they do fits into any larger picture 3) the brilliant, innovative and humble contractor :-).