Campbell
Relaxed Intensity
If 13th Age or Dungeon World counts I'd go for one of those. If not, I'd probably go with BECMI - it lacks quite a bit of what I like about 4e, but also doesn't have a lot of the features of AD&D and 3e that I adamantly dislike. I'll play Basic any day, particularly if I'm actually in the mood for dungeon crawling. Pound for pound I find the game more thematic, better balanced, and and more adept at the sort of games I want to play than AD&D or 3e (far less focused on dungeon crawling past initial stages of play).