What decade is this?

I was working the other day at my hourly job, leisurely handing out samples of italian pasta, enjoying interactions with customers when I made a comment to one of my co-workers. I told him I thought it was funny that all the media outlets touted 2009 as the end of the Decade. They were saying 2010 was the start of the new decade when, in fact, 2011 is the start of the next decade. He immediately said, "your wrong, 2000 was the first year of the decade, so 2000-2009 was the first ten years." Thus started a lively, good-spirited debate on whether one counts 'zero' as a year. A customer overheard me and gave her input by saying to me ,"your wrong, he's right". She gave no argument for her position. She simply stated I was wrong, enjoyed a food sample and some free coffee, and continued her shopping. Well this got me wondering, "who is right? What decade are we in?"
Media outlets like the NY Times posted articles titled "Reflections on the First Decade of the 2000s", Business week titled an article, "Tumultuous first decade of 21st century comes to merciful end". Chicago Tribune "On to the next decade...", ABC News "End of the Decade", The Washington Post's Anne E. Kornblut wrote;
'It is my pleasure to push the button on this, the final White House pool
report of the decade.'
It doesn't take much searching to discover our calendar is the Gregorian Calendar. There is no year ZERO in the Gregorian Calendar. The year 1 A.D. is preceded by the year 1 B.C.E. Hence the decade would be years 1-10. The year 2000 was the tenth year of the final decade of the 2nd millenium. 2001 was actually the first year of the 3rd millenium. What are we going to do next year when we get to the actual end of the decade? Or will the Media, businesses, and Government continue to ignore this mathematical error?