My first D&D was AD&D 2nd Edition, and I still like it best, although I don't play it right now, and haven't played since school. There are quite a few things I'd houserule, and I'd drop most of the optional rules, so in its essence it would be D&D, and not advanced, but gone back a few steps. I run Basic Fantasy in a similar way.
My second D&D edition was the BECM sets of which I loved the Companion rules best. I never played that edition. I'd love to read through the books again, but they're gone.
That being said, I love Dungeons&Dragons. Retroclones, simulacrum games, or the original. And yes, I'd probably buy D&D Next one day.