It's true that Warren Buffett holds KO, but that's a far cry from saying that he'd buy it now. Not only has he mentioned that the market is overvalued in his Letters to Shareholders, CNNfn and the Washington Post, but he mentions that paying too much for even an excellent company isn't the greatest investment strategy.
Berkshire Hathaway started hoarding up on long term bonds a little more than a year ago. I believe their 10K SEC filing indicates that they currently hold around $10 billion in "Securities with fixed maturities".
In addition, lets all keep in mind that Warren Buffett's average cost when purchasing KO shares was in the range of $5-6 per share (unadjusted for inflation).
If you hold KO, great. But if you don't, I'm not sure this is the best time to buy anything. Of course Buffett was ridiculed for saying the same thing in 1969-1972...