The Jubilee line is like something out of the Jetsons. Hands down the finest subway I've ever been on.
That's the 'new' portion of the line from Westminster on east to Canary Wharf, North Greenwich (the O2) and Stratford, opened 1999 - makes for much easier north-south travel to the Houses of Parliament area (prior to that you had to take the Bakerloo or Northern to Embankment, or the Victoria line to Victoria, and then take the Circle/District line)...also the first fuly wheelchair-friendly sector of the system.
