For Heavy bomber, I am going to have to side with the Avro Lancaster over the B-29. Even though the B-29 was more advanced and could out preform the Lancaster, it was almost too advanced and suffered early on from many malfunctions, this counts against it. It was also not nearly as versatile as the Lancaster which had many variants including para drop resupply, airborne assault, heavy bombing using the Tall Boy bomb, Dam busting, incendiary bombing of cities, ELINT, Electronic Warfare, and Radar equipped versions to lead and cover the strike group.
Both were modified and used in Korea (the Lancaster as the Avro Lincoln)
For a Ground Attack aircraft, no question, the IL-2 Sturmovik.