My top choices would be:
Cathay's Pier and Wing lounges (tie)
Most notable feature- noodle bar!
British Airways Heathrow Terminal 4 Lounge
Most notable feature- complimentary services offered at Molton Brown Travel Spa
Honorable mention would be new Northwest WorldClub in Detroit- fireplaces and hot chocolate went well together there.
Of course, much depends more on where one is based. Out of IAD- I prefer BA and NW/KL lounge whereas out of DCA I prefer CO/DL lounge.
------------------
"Fly me to the moon and let me earn alot of miles."