Macross.
It's got everything, great characters, drama, action, singing, and planes that transform into robots. Planes that transform into motherfucking robots man!
Pity almost none of it ever gets released properly outside of Japan, thanks to Harmony Gold being a bunch of dicks over the license (that they probably should never have had in the first place, thanks Tatsunoko). It took 20 years to get the first season properly, and only that and Plus are out at all. Macross 7 is never getting translated (no-one can afford it), and even Zero didn't come out.
Which is madness, because Macross is big news in Japan. Macross Frontier's first BD release was the highest selling Blu-Ray disc of 2008 in Japan (not just anime, all BD releases), and was probably the most staggeringly awesome series of the decade (and that includes Tengen Toppa Gurren Lagann).