I agree with you in a sense. However, I have had GREAT results from Inktomi and Fast (Especially Ink.). I just had to learn which pages to pay for and which ones weren't worth it. If I had to choose one page to submit, I would choose a page that has the most keywords included on it.
If you sold Calendars for DOGS, you would probably be better off submitting a page that listed all of the dog breeds rather than submitting your front page that maybe just said "DOG CALENDARS" and had a picture of ONE calendar.
If you have a page that has a complete list of all calendars/dog breeds, you would probably get more hits submitting this page. You will more than likely get more hits from a page that has "German Shepherd Dog Calendar, Bassett Hound Dog Calendar, Great Dane Dog Calendar, Poodle Dog Calendar, etc. etc. etc." There are definitely situations where your main page is not the best page to submit.
You do need to pay close attention and submit to each search engine differently than the others.
It is true that most PFI engines will not spider your site if you are paying for inclusion. As far as FAST dropping your site, I have been having a similar problem, but when it happens, I find the people at FAST are WONDERFUL about helping me get the listing back up. However, I do have to admit I have a good contact at FAST that is really helpful.