I am loving my D&D/C&C experience right now. I am a player in an AD&D 1st edition group, and I am running a C&C (Castles & Crusades) group which structured in an old school way, with some modern innovations.
However, I recently got a hold of the good old (Moldvay) B/X Basic D&D box set from 1981 as well as the B/X Essentials (which includes the 1981 Basic and Expert rules that take characters to 14th level and organizes the information differently for easier and quicker reference). The fact that it currently comes in 5 separate books makes it an easy reference for different people at your table (one person might be choosing a character class, another might be choosing spells, someone else checking up on a rule, etc).
Now I have a desire to be part of a B/X campaign! It would take me back to when there were only four classes, and the races like elves and dwarves were races and classes in one. The simple elegance of this is attractive.