Since there's been such good discussion on this, would anyone care to try and rank the various 5k/10k doublers (and one marathon tripler) over the years?
My thoughts:
1 Bekele 2008 - simply decimated the field in an OR 5k. 10k also an OR, I believe. Although we all know time doesn't matter in championships, I have a hard time not being impressed by someone who sets a record AND wins a gold
2 Zatopek 1952, 5-10-mara - the only one to win all three. Can't imagine anyone doing this again. Or even attempting it, really.
3 Viren 1972 - fall and still set a 10k WR at the last fully attended Olympics for 12 years. Proved he could win off a fast pace there, or a slow pace with a long drive for home in the 5k. In other words, proved he was unbeatable, at least for a week in the autumn of 72.
4 Farah 2012 - The best man won, but not in the most impressive manner. I don't really take into account what opponent's PRs were, at all Olympics you have that era's best runners. Other people may disagree (and do, based on this thread)
5 Yifter 1980 - Games not fully attended, though probably most of the people who would have contended in the 5 and 10 were there. The Kenyans weren't really that strong at 5 and 10 yet, though they would be by decade's end.
6 Viren 1976 - also not fully attended. Many African nations boycotted, including Ethiopia. Just four years later that nation would go 1-3-4 in the 10k, for example. Though again it wasn't as watered down as it would be if African nations had boycotted these days. Still, I think this was less impressive than his 72 double but others might disagree.
Unrankable: I don't have much knowledge about Kohlemainen 1912 or Vladimir Kuts 1960. Don't think it would be fair to try and rank 'em.
Surprisingly (to me anyway) no one did the 5-10 double in one Games when Ritola and Nurmi were the stars of the 20s. Both had 10k and 5k titles at separate Games and both men did other doubles within single Games. Might also be fun to consider 15-5k and other doubles (Ritola did the 10k steeplechase double in 1924) but I've gone on long enough I think.