Out of curiosity, the posters of every 10,000th post are:
10,000: Starkey (a haiku from a 2006 Bottle Challenge)
20,000: Tubeguru (a review of GTA IV)
30,000: Palkanetoijala31 (answering a question about one of his FNC routes)
40,000: Going Underground (discussing an R15 twist)
50,000: Geofftech (sharing two interchange tips, both of which are now quite well known)
60,000: Iain (commenting on a 2012 FNC attempt)
70,000: Tractakid (a Google Street View Treasure Hunt post - wow, that takes me back)
80,000: Soup Dragon (talking about an appearance on TV)
90,000: Iain (again!! Posting something in The Snake thread)
All London buses: 23 hours 25 minutes (with Adham, David, Josh and Tangy)
Holds some alternative challenge records. Not sure which ones.
20½ Random 15 challenges: 01:58:48 best
That guy who runs those Twitter polls about tube stations and London Boroughs.