I know this is really really homo of me, but i still listen to that song once in a while haha. i guess that is one of my guilty pleasure songs. certainly not the best of the 00's of course.
It's so hard to narrow things like this down. 9 years of music down to the best song. like said above, different stuff for different moods. My roommate and I both loved limb bizkit in our teen years and still go back and listen to those albums and shout the words, it's so funny.
as for the best, I wouldn't even know where to start.