I think the sexiest design is still the Mustang. Unfortunately,
they only realised the mustang's full potential near the end of the
war. The mustang was actually in service very early in the war, as
early as 41 or 42.
They served in the RAF, as recon and light ground attack fighters,
as its original allison engine was considered inadequate.
Strangely, the merlin was already around at this time, it just didn
occure to the yanks or the brits to put these 2 together. =/