I think we'll find that as Yahoo and MSN develop their new search technologies, we'll see more competition in providing less artificially manipulated search results. For example, I just read MSN's new technology will involve statistical analysis to specifically weed out link farms and sites that are too "artificial" in their linking strategies.
Incoming links are an important off-page measure of a page's relevancy. But more needs to be done to assure these links are real "votes" and not just artificial ballot box stuffing. I sense G has grown lazy with developing their algorithm to defeat Googlebombing. It's obvious (to me) the push for a better G (less artificially manipulated results) isn't going to come from within - or Googlebombing should have become less a problem by now. Thus I welcome Yahoo and MSN's more serious entrance into the search arena, as I feel they will provide what real competition generally provides - a better product.