This post represents a correction from a brain fart while writing the previous post. While writing that post, I could remember only four of the five paths I use for dungeon design. All I could remember was the Architect DM piece. While I like that bit of info, it wasn't a part of what I had intended to write. Here is what I originally intended to include as one of my Five Paths For Dungeon Design:
The 5 X 5 Method: This allows the GM to create some plot, setting and thematic connections for the players to follow while allowing players to make significant choices as to where they are going and how they will play. Basically, the GM identifies five different quests, locations, factions, etc. In turn, each of these five quests/locations/factions/etc has five episodes, modules, or actions associated with them.You can find a the 5 X 5 Compendium here (with links to a number of blog posts and articles) but the original article (here) and an an example of how this method was applied to The Temple of Elemental Evil (here) gives a nice overview of how this method can help to plan a dungeon campaign.