Mass. Sen. Brown to colleagues: 'We may obviously meet again'

His farewell address echoed the main theme of his campaign: that he's one of the most bipartisan Senators in the upper chamber, and that he's worked to be an independent voice for Massachusetts.

"I'm proud that I did keep that promise to be independent, and I'm proud that my voting record has identified me as the second most bipartisan senator in the United States Senate, as referenced by Congressional Quarterly, and I was named as the least partisan senator in the United States Senate by Washingtonian Magazine," he said.

Brown also touted the three times he had been invited to a bill-signing at the White House, for the bipartisan work he had done on legislation during his more than two-year tenure.

Brown lost by about 7 percentage points in the final count, but ran a strong campaign for a Republican in a blue-leaning state. He argued frequently that he would be the most bipartisan of the two candidates, and even featured shots of him with President Obama in some of his ads.

But Warren worked hard to tie him to a potential Republican majority in the Senate, and that, coupled with a boost in turnout from the top of the Democratic ticket, helped launch her to a win.

Warren will join the Senate in January. She says she has spoken to her former opponent, and that their conversation has been cordial. She's already staked out a spot in the Senate Banking committee and has expressed support for filibuster reform, which Democrats could pursue on the first day of the new session.

Though Brown didn't mention Warren in his farewell speech, he did seem to criticize the proposals for filibuster reform, which could become one of Warren's first pet issues when she joins the Senate.

"I'm deeply concerned about any changes in the rules that are being proposed to eliminate the ability for both sides to battle and do battle in a thoughtful and respectful matter," he said.

Watch Brown's farewell: