Google webmaster tools gives decent report for your own site, the commercial services that give limited free results include opensiteexplorer.org and backlinkwatch.com neither scours each of the trillions of pages, but it will probably be thee worthless junk backlink souces they overlook.

For the actual tracking, using tools like Google analytics or statCounter one can determine the number of direct visitors a given link is giving (vs the search traffic the link indirectly helps)

Some SEOs advise removing backlinks that have never brought in any direct visitors. They are probably negative ranking factors.

My personal favourite would be SE Ranking. http://seranking.com. Its a powerful SEO Ranking Tool where ALL THE OPTIONS for tracking website rankings are gathered together in a single service. Very simple User Interface. With Google Analytics integration you can monitor your website's search engine rankings side by side with the number of visits, keeping general traffic statistics always at hand.

I think Google already given so much, they have also made Google analytics which is pretty good tool for tracking and monitoring everything does on your site.

Google analytic and webmaster is best tools to track your site visitor.

backlinkwatch and opensite explorer