I'd say to go with whatever works for you. I use a mixture of ear and reading music. I got started reading music early, taking piano lessons mixed with theory for six years as a youngling. For the instruments that I play (flute, sax, piano, a bit of whistle) I rely a lot on reading the music because that's how it was taught to me. However, especially with the flute and piano, I do try to learn stuff by ear, because there's a lot of music that I only have in recorded form.

Vocally, I use ear and eye more in balance. If I'm singing a piece that I've seen the music to, I visualize the music in my head because it helps me to remember. But otherwise, I learn vocal music best by seeing the lyrics (so I can visualize those to remember them more easily) but hearing the music.

By the way, just curious. How many other people out there shamelessly improvise vocal harmonies at the drop of a hat? I do it constantly with whatever music I happen to be listening to at the time, and sometimes I can even do it off the cuff with music I've never heard before. It's great for developing the ear, and oddly enough, knowledge of music theory does come into play a lot, at least for me. I.. I'm not sure how to explain. I visualize the interval, or the shape of the interval. Knowing chord structures and basic harmonic patterns enables me to pick out where to place myself in the chord.

Slán,

Kiwi