No one has mentioned the Marble Arch Marriott which I like as well. It's closer in city yet only a few blocks from Oxford Street, Marble Arch, Hyde Park. You have within a few blocks several tube lines- Circle, District, Hammersmith City, Bakerloo (edgware Road Station) or the Red (Central) line (Marble Arch). Also, several buses are but a 1/2 block away on Edgware Road - to Picadilly/West End or to Victoria or Knightsbridge.

LHR to the hotel is easy - buy an all-day 6 zone pass at LHR for 6 pounds and take the tube to Hyde Park Corner. Exit and get on the 444 Edgware Rd bus and get off a few minute later 1/2 block from the hotel (George Street).

You can use the pass the rest of the day for both buses and tubes.

If you are Gold they will usally give you lounge access. Last time I was there the lounge did not offer its breakfast serve but rather full buffet in the restaurant (better deal). But the lounge was available until 11p for snacks, soft drinks and coffee/tea service.

Hotel has small workout area, pool, sauna!

Also, I'm staying at the Chancery Court this week. Love the location. Picadilly line from LHR to Holborn tube stop. Hotel is 1/2 block from tube stop (you don't even have to cross a street). Buses to all the attractions are on the corner around the tube stop. Walk to covent garden, etc.. Lovely building too.

Good luck