an_idol_mind
Explorer
I'd cast my vote for Moldvay/Cook. The 1974 boxed set is a nightmare to go through as far as editing goes, though if you go with that I'd recommend using it without supplements (my preference only). The Mentzer BECMI rules make for a solid game, but has a lot of extraneous stuff added on that I think takes away from the simplicity and appeal of the game. The Rules Cyclopedia (which is a compilation of the Mentzer rules, really) is a great resource, but has a lot of optional rules that usually turn into wasted space for me. Moldvay/Cook is great for fast, no fringes gaming, if that's what you want.