WRAPUP 8-McCain and Obama battle in contentious debate

* McCain and Obama complain about each other's tone

* Rivals clash on taxes in final debate

* Polls show Obama with edge over McCain

By John Whitesides, Political Correspondent

HEMPSTEAD, N.Y., Oct 15 (Reuters) - Republican John McCain and Democrat Barack Obama battled fiercely in their most contentious debate on Wednesday, with an aggressive McCain attacking Obama's campaign tactics and tax plans in a showdown that made a star of "Joe the plumber."

The presidential rivals complained bitterly about the negativity of the campaign during a series of testy exchanges that included repeated appeals to average Americans through references to Joe -- the owner of a small plumbing business Obama met in Ohio.

McCain was on the offensive throughout the 90-minute encounter. He rebuked Obama for his frequent claims that he is too close to the policies of President George W. Bush.

"Senator Obama, I am not President Bush. If you wanted to run against President Bush you should have run four years ago," McCain said in the final presidential debate, held at Hofstra University in New York.

Obama, 47, said he sometimes had trouble spotting a difference between the two.