Well, my group has agreed to the Labyrinth Lord campaign, which will now start on April 3rd, giving me three weeks to get all of my ducks in a row. My first choice is exactly which iteration of Labyrinth Lord to use, a decision that has recently become rather more difficult. As far as I can see, there are four different choices.
This one would just use the Labyrinth Lord corebook. Basic seven classes, and a set-up that all of my players are familar with.
Labyrinth Lord + Original Edition
Going back to the '74 set-up with the Original Edition Sourcebook. I actually rather like this idea, but I'm ruling it out as some of my players are concerned it might be a bit limiting.
Labyrinth Lord + Companion Expansion
Essentially Labyrinth Lord with some extras added on - seven new classes, some new spells, and so on. The advantage here is that the complexity is not increased at all, as all of the additions bolt on without making any fundamental changes.
Labyrinth Lord + Advanced Edition Companion
Taking it to essentially be 1st Edition AD&D. While I like the sourcebook, we've only recently come off an AD&D campaign, so I think I'm going to rule this one out.
It looks like I'm going to go with option three; more options, more classes, no additional rules complexity. One sourcebook I will definately use is the Creature Catalogue, but I'm going to keep it to just those three sourcebooks for the sake of portability. Another advantage, of course, is that free PDFs of the two book the players will need are available.