Sally D,
Your logic is ridiculous.
1) How is it that when I defend my position I'm a "stubborn 10 year old boy" and yet when you defend your position you aren't? Here's a thought - we're both defending the position we believe is true - you just happend to be wrong.
2) Head to head is NOT what counts. That's the silliest thing I've ever heard. One guy could be down that day for whatever reason, or he's on the rise toward his peak in that distance, etc. etc. etc.
3) I have nothing against KK. When he held the world record and this same question came up, I said he was the best because the time said so. We start the clock when the gun goes off for a reason, and we record record times for a reason. The best have the fastest times. Period. Someone could win 10 championships in a row and beat another runner each time, but the moment that other person runs a faster time, regardless of whether the other person was in the race, he is the best. Perhaps not fair, because perhaps it was just the perfect day and perhaps that championship guy would have beaten him on that day, but he wasn't there and he didn't.
4) Tergat holds the world record in the marathon, and so he is the best marathoner in the history of the world. There is no room for debate. Anyone EVER wanting to debate such an issue is trying to be intellectual where it isn't needed. It is easy to see who is the best in any distance - just look at the world record books. The name you see there is the one who is the best.