Please mention the airline it is from. IMO, BA has the nicest uniform (I prefer double-brested jackets any day), closely followed by Qantas’ new uniform (I love the white hat).
Edit: I just feel that double-breasted jackets for pilots project a more formal, professional look.
Edit 2: Just saw Pan Am’s uniform- tied with BA as my favourite now!
Virgin America has the best looking ones IMO. Different from the simple black and white ones. I like these especially because you don’t have to wear a tie. :)