Well here is my 2/- worth.
Where do you start? DH4? from WW1 or may be the HP100/400s?
Inter wars the Virginia or the Fighter/Bombers that patroled the rather more inaccessable parts of India? When the pilots carried Goolie Chits?
Or the Hampden, Wellington or Blenhiem that carried the load in the begining of WW2?
Even the TSR1 might get a gurnsey. It was the direct cause of the attack on Pearl Harbour!
During the latterdays of the second world war the Lancaster reigned supriem as the greatest heavy of all time! Stick that up your B17s (You can take a Flying Fortresss to 40 thousand feet. But it only drops a teeny weeeny bomb! Singing where oh where shall we drop it. Cause we've only got a teeny weeny bomb!).
while the Mossie was the best alrounder.
In the Pacific the honour would go to the Beaufort/Beaufighter, although if the Woomera had gone into production that may have been a different story.
Post war the Lincoln, the three Vs, Canberra and the Might Have Been TSR2 all make great claims.
However having said all this I would give my final vote for the.......Lancaster! Versitile,adaptableand the basic airfraim lived on in many other aircraft......Lancastrian, York, Lincoln,Long and short nose, and the Shackelton.
Now having set Anglo/US relationships back about 50 years I will take my soap box and get the washing in!
Dai