Copied from other thread 'cos it belongs here really.
I took the Overground to the Geffrye Museum yesterday and it was so quick! I think I got to Hoxton in 17 minutes if I'm not mistaken. I used to study nearby and remember getting stuck for ages on the 149 bus out of London Bridge - often the journey from Forest Hill would take over an hour.
Hoxton station also takes you to the nearby Troy Cafe on Kingsland road, which I highly recommend.