So, I don't know how useful this will be to some people, but Dwarven Forge released a nice "dungeon layout" tool for people who own Dwarven Forge stuff, so you can doodle and mess around with setups without leaving the computer. However, this can also be used as a tool to create and print dungeons for people who may be wanting to do some role-playing etc. I know this is a miniatures-based forum mostly, but it's a cool little tool.
Thought some people might find it handy.
http://www.dwarvenforge.com/mapmaker/PS: I haven't messed around with trying to print anything yet, so I don't know if it's really worthwhile for D&D etc. Could be?