I might be meeting some Chinese friends in London this fall and could use some help. If we stay in the city center to be within easy reach of traditional tourist sights, are there named areas (like Knightsbridge) that are better than others? Are cabs a reasonable way to move about or should we focus on proximity to the subway? What are some of the less well known, but interesting things to see within London? How much time (in days) should we allocate if we restrict ourselves to London and aren't in hurry? What are the best day or two day trips to take if we rent a car and head out of town? Other cool advice is welcome. Thanks.