How do we get unbiased search engine results from Google and the like?

I have found it increasingly difficult to get unique and different web site results from Google without seeing an obvious bias towards some similar (or the same!) sites. Have you had a similar experience with this search engine or another one you are using? Is it the cause of the search engine, or the fact that one entity/company/organization is clogging the engine using their high optimization skills?

If this is not a universal situation among all search engines, can you suggest some good alternatives to Google?