Hi Thraug, welvome to the wonderful worlds of WWG

2. Are "Classics Combo" and "DungeonWorks" 1" or 1.5", or other?
Dungeonworks is 1". The CastleWorks part of the Classic Combo appears to have been loosely designed around 1" (e.g. the wall walks are about 1" wide) but doesn't actually force 1" as it isn;t marked with 1" grid.

3. What sets are and are not compatible with one another? I've seen mentioned several different style types: "Free-form" (Chunky Dungeons), "Floating walls" (Gothic Relmas), "Place-as-you-Play" (UnderCrypt), and "2d floor tile" (DungeonLinx).
The floor tiles are all interchangeable, and I've used them that way. The Chunky, DungeonWorks and Gothic Realms walls all have different profiles (rectangular, triangular and flat, respectively). They can be used progressively as you move through different sections of a dungeon. However, the smoothest integration is with the flat walls (Gothic Realms, CaveWorks, and the DungeonLinX props) - and will also align with the new material Denny is producing (e.g the Pathfinder stuff).

4. Which sets have options for curved areas (walls, corridors, rooms,etc.)?
The Chunky sets include curved walls, and Gothic Realms walls can be bent into curves.

5. Has Denny's "new" system (mentioned around Feb 2009) been revealed yet?
As LD said, not as such. However, from the timing of Denny's announcemnt, I'm guessing that the Pathfinder sets are a pretty good indication of the direction: using premade 3D units with flat walls that fit together in interchangeable ways, probaby with a tendency to work with 6"x6" tile formats.

Reading between the lines of your post I'm guessing that Gothic Realms may fit your (implied) criteria perfectly: excellent (I do think this is the best dungeoneering terrain), easy to construct dungeon terrain that is (by all indications) also consistent with Denny's new direction.

Did you discontinue classics combo?

[quote="Gamesmith Denny"]

Its funny that even with such a small business, you have to guard your secrets like Nike It feels a bit silly sometimes but eyes are definitely on us and what we do here.
quote]

Thats because your the best at what you do

Keep up the good work