So, people have summed up your questions pretty well, so I'm gonna flog my favorite horse for y'all...
Basically, there are two games (that I know of) that do a great job of recapturing the early days of D&D, and they do it in radically different ways.
Castles and Crusades, by Troll Lord Games, really combines the character-creation simplicity of old D&D with a lot of the systems simplicity that you got out of d20. You can pretty much make characters in C&C by handing out xeroxes of the preferred class and race combo of the players, and having them roll stats. Almost all actions boil down to "roll d20+modifiers. Try to equal 18 or better." It has the added advantage of being almost directly compatible with all of the old modules; aside from the AC switch (to ascending ACs), you can pretty much drop anything from AD&D into C&C without any more consideration. Even XP is directly portable.
Hackmaster is different. It recaptures some of the system complexity of earlier games, while still making a concerted effort to have those systems make sense when viewed together. This means rejecting some things that C&C retained (HM wizards use spell points, not spells-per-day), and reinventing others (such as using active defenses, armor reducing damage, and shields being important).