Leicester Square to Covent Garden (250 metres away)
Mansion House to Bank (change once, 6 stops - as noted by Bill Bryson in Notes From a Small Island (though you could walk to Bank districtline and go in two stops, but his point is still well made))
Chancery Lane to Farringdon (change twice, 4 stops)
Even Finchley Road to Hampstead (change twice, 9 stops) could be walked in half an hour, although what neither map will tell you is that it's up a steep hill.
Related: V-2's Why the map is not the territory (geography and schematic maps are different; sometimes schematisation goes too far)
Also, the Tube's Tubeguru interactive map (IE only we'd recommend) provides more contextual information (geographic, local).
Voda, T-Mob and Orange says it's bad for (49m mobile) consumers as (eg) handset prices will rise; Voda says Oftel miscalculated costs to the networks, and therefore is seeking a judicial review