My personal favourites are the Covers of the German and the French Issue,
beachy, summer feeling evoking :)
Gweneth Paltrow's Cover is refreshing, too.
The UK one is fabulous, too, because of the adorable miu miu dress.
(Lily Allen wears a similar one in lilac on this moth's ELLE UK Cover)
After all, I think this moth's issues are all very very well done, there's any cover I do not like!)