Great list! I have a few to add:
Tiled Map Editor http://www.mapeditor.org/
Tiled is a general purpose tile map editor. It's built to be easy to use, yet flexible enough to work with varying game engines, whether your game is an RPG, platformer or Breakout clone. Tiled is free software and written in C++, using the Qt application framework. The main features in a nutshell:
General purpose tile map editor with XML-based map format
Supports orthogonal and isometric maps
Custom objects can be placed with pixel precision
Full undo/redo and copy/paste support
Add custom properties to tiles, layers, objects or the map
Automatically reloads tilesets when changed externally
Resize or offset your tile map later as needed
Efficient tile editing tools like stamp and fill brushes
Supports input/output plugins to open and save files in custom formats
Tile Studio http://tilestudio.sourceforge.net/
Tile Studio is a complete development utility for graphics of tile-based games. The application contains a bitmap editor for creating tiles and sprites and a map editor for designing level maps.
Tile Studio was originally designed to be used with the Game Library for the language Clean (a functional language, developped by the University of Nijmegen). But Tile Studio can be used together with ANY programming language, since the output is completely programmable! You can program Tile Studio to output your maps, animation sequences, bitmaps, palettes, etc. in any format and include the output directly into your source code!