II, III, and IV are awesome. I think I, Houses of the Holy and Physical Graffiti are waaaay too much underrated, and that's why PG is my fav.
I'm a huge fan of Led Zeppelin, but except for Achille's Last Stand and Nobody's Fault but Mine, I really don't like Presence. I haven't got yet In Through The Out Door or Coda, but I heard they were pretty bad... Are they?