Hmmm, I notice that no other 3D paper terrain made the list.

Looking at the list I have:
A Magical Society: Ecology and Culture
Fractal Mapper 7.0
Steam & Steel - A Guide to Fantasy Steamworks
WorldWorks / VillageWorks 3-D Village
WorldWorks / SeaWorks: Maiden of the High Seas
In the Saddle: Horses and other Mounts
The Elements of Magic

I also have the unrevised Everyone Else and a bunch of others that did not make the list. I rather like PDFs.

The Auld Grump, Fractal Mapper really isn't a PDF though, but I have been using it since version 4.

Things that I am surprised not to see on the list - Gothic Realms, Sea Works: Skull Cove, and either of the Interior Works sets.

I am not surprised by Arena Works not being there - while it is a great set it is very focussed. But it is a wonderful set, perhaps you can get together with somebody to cross market it? Mongoose had a supplement for D20 called Sands of Death, perhaps something similar? Or a scenario involving chariot races for one of the WW Adventures? It is just one of those sets that if you need it you need it, and if you don't you don't. But once you have it you think of reasons to use it.

The Auld Grump who needs to build a new arena...

*EDIT* Hmmm about a line of text was missing... I must have typed over it instead of inserting text.

Congrats, indeed! The competition there on the list is impressive, so you should definitely feel pretty good.

As a side note, it does my heart good to see that Pinnacle/Great White Games is in the top 5, too!