CodeBlocks: one of the best IDE for Arduino

CodeBlocks Arduino IDE is a customized distribution of the open-source Code::Blocks IDE enhanced for Arduino development. It provides more demanding software developers with everything a modern IDE should have including code foldering, code completion, code navgiation, compiling as well as uploading for Arduino. With a dedicated project wizard, it’s easy create a ready-to-go Arduino project. The distribution integrates latest Arduino core files, standard Arduino libraries, AVR toolchain, Arduino Builder, a serial terminal and most interesting, an API-level Arduino simulator (under development).

Other alternatives can be found under http://playground.arduino.cc/Main/DevelopmentTools