I'll second the Chamber of Eyes.I like some of the encounter areas in H2 Thunderspire Labyrinth. I've GMed the Chamber of Eyes and the Well of Demons. Both have good locations with lots of circular paths and interesting terrain.
The actual encounters, as written, can sometimes benefit from a bit of work. For example, I ran the encounters in the Chamber of Eyes as one big encounter rather than in sequence. Similarly for the gnolls in the Well of Demons. If you run the encounters as written then you won't get the full benefit of the interesting maps.
No, but that's not what I'm looking for. See pemerton's post (#13, above) for a good example of what I'm talking about.Are we even allowed to post published encounter design material?

I'll second the Chamber of Eyes.
The best 4e encounters are the ones that follow the late 3.5/early 4e advice of making encounter areas larger, and composed of more than one room.
I dunno.Yeah... Whatever happened to that bit of wisdom? Why didn't it get any followup?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.