by xipuloxx
I have most of the expansions, but by no means all. I pretty much always include Inns & Cathedrals, which "completes" the game for me. Apart from that my most commonly included ones are:The Phantom (1 transparent meeple per player, which can be placed at the same time and on the same tile as an ordinary one, and that's all). I like the extra options it gives; if you feel an extra meeple is too much, just replace an ordinary one with it instead of adding it in.
Traders & Builders (2 new types of figure, but the changes they introduce are interesting, especially the Builder, which really shakes thingsup by giving you extra turns sometimes, and trade goods which give you a tactical reason to finish other people's cities).
King & Scout (new tiles which fill in "gaps" in what's available, plus an interesting bonus for completing large cities and roads).
Most of the others are interesting, but not things I often want to include. But they can help spice the game up when I want something that's Carcassonne, but a bit different. I haven't tried Plague, Tunnels or Crop Circles (was waiting for the expansion that combined them, which is now in limbo), but they all sound good.