Hoody Hoo! Basic D&D rocks! Nothing like having elves and dwarves as classes.
Currently I am playing in a Hackmaster campaign where our adventureing party, The Iron Trifecta +1, is currently clearing out the Mines of Chaos in B1: Little Keep on the Borderlands. Our GM is awesome and the players are really experienced. We tend to spend the majority of every session just role playing in the Keep and it is only in the last session that we got into some real dungeon hijinks. I'm having an absolute blast.
I also run a D&D 3E game that is kind of on hold (I think my profile has a link to the campaign site I put up). My group for that game has been together for over 6 years. We just finished up a year long campaign and have started this new one...which is not going very quickly.
In addition to that, I'm currently trying to modify AD&D 1E with some of the rules from Hackmaster and from 3E. Not a huge makeover, but a few rules to smooth out gameplay (spontaneous cures for clerics, HM initiative and skill system).
As for the best game I've ever played in...that's actually hard to pick as I don't play all that often. The best game I ever ran was a Deadlands (my favorite RPG) one-shot that literally gave people nightmares and everyone had fun...that's my high-water mark.
This post has made me think of what a huge rpg collection I have and how few of the games I've actually played.... It might be time to clean out the closet