Looking for software to create maps or dungeons

[huginn]

I am looking for software to create maps and dungeons or do a layout of a town
Does anyone use some software package to do this?

[Beleriphon]

Dundjinni, relatively inexpensive with a free demo, mostly tile based: http://www.dundjinni.com/
AutoRealm, free has a few fun functions, CAD based: http://autorealm.sourceforge.net/
Campagin Cartographer 3, expensive (for all the functions its hundreds of dollars), powerful professional results, CAD based, very high learning curve: http://www.profantasy.com/default.asp
Ye Old Mapmaker, free, web based as well, iOS and Android apps cost money (like $1.99): http://yeoldemapmaker.com/

[ArgentumRegio]

For every campaign I use the following

LIBRE OFFICE for notekeeping and such.
AUTOREALM for general mapping
GIMP for worldmapping and more
EVE (http://goosee.com) for diagrams and much much more

With these, a thumb drive (backup often multiple copies) and a good wiki, the whole campaign travels with me in my pocket. :D

[Gnoman]

There is a tool called Grid Cartographer 4 that I like to use for encounter maps. It was originally intended as a simple tool to map older grid-based CRPGs such as Wizardry or Might and Magic, but over time evolved into more. It has a handy export-as-image tool, handles multiple levels fairly easy, and is trivially easy to operate.