I find myself unable to get very excited about any of these. The Castle Greyhawk book seems like it'll be in the same format as the Castle Ravenloft one, and while other people seemed to like them, I didn't care for the two-page encounter spreads at all. Likewise, a MM5 that's in the same format at the MM4 doesn't seem like anything to get all hot and bothered over. The drow book looks interesting, I admit, but I wonder if I'm reaching my saturation point on the Complete books.
Maybe I'm just becoming jaded, but these all seem like products that somehow fall just a bit short of being exciting.