I've stayed in nondescript B&Bs in Earl's Court, the Observatory House at the top of Holland Park, the Grosvenor at Victoria, and a few in Bayswater. But the one I enjoyed the most was the (sparkling new) Days Inn Waterloo. It's diagonally across from the Imperial War Museum, and the bus will get you to Westminster (159) or Waterloo (59) in 5 minutes. Lambeth North station on the Bakerloo line is at the north end of the block. Walk to pubs, restaurants, and groceries. What's not to like?