Dinner by Heston Blumenthal -- great British fare with a lot of twists. Reserve on Open Table. Reservations are fairly easy to get. You do need to put down your card though.

Gymkhana is very good -- Albemarle Street! Very posh. Reserve on their website.

Berner's Tavern is really disappointing -- at least for me and my friend.

If you are looking for English traditional fare but very upscale, try Wilton's.