I disagree with you.
If Huckabee pulls out, then McCain could potentially win Alabama, Arkansas, Georgia and Tennessee. With Huckabee staying in, he could win delegates in those states and thus prevent McCain from getting any of those.
Similar reason as to why Giuliani also needs to stay in and somehow defeat McCain in NY, NJ, CT and hopefully CA. In those four states, I think Giuliani is the only candidate who is competitive with McCain.
Hopefully, Romney will go after states like Missouri, Illinois, Minnesota, Oregon and some of the others on Super Tuesday that I didn't already mention.