Depends. For example (IMO), the Boeing 777 (especially -300ER) is just hands down BEAUTIFUL! Same with the 787, 747 and the 330. On the other hand (again, IMO) the 380, as comfortable as it is inside (flew DXB
on one last month) is a chubby "dwarf". Many NBs get boring quite soon, but I've always liked the 737 (with winglets). Also, the 757 is beautiful. Embraer jets are nice too. Both E135/145 and the E-Jets.