Well, without getting into the personal details of cities you may wish to visit and why, the best place to buy a *ONE* ticket depends on class. Until recently, MRU has been the least costly for first class tix, but has been replaced by South Africa, due to the nosedive of the rand. Note that if purchasing in Africa, you must by a four continent ticket. Unless you are completely price insensitive, you don't want to purchase tix in US or Canada, as these are two of the most costly places to purchase, regardless of class of travel. The LHR-MRU non-stop leaves LHR in the late afternoon, so I'd certainly think about overnighting to LHR and connecting. Also, consider using points for a one way ticket to MRU, then buy your RTW ticket there.

You can correspond with BA MRU at [email protected]. I always make my reservations by e-mail that way.

Good luck, and enjoy the ride !!!