Eclipse - Eclipse is an open source community, whose projects are focused on building an open development platform comprised of extensible frameworks, tools and runtimes for building, deploying and managing software across the lifecycle.
NotePlan - Make plans inside an individual markdown note for every day in your calendar. Use it as a journal for your daily tasks and plan todos in advance. For Mac, iPhone and iPad.
IntelliJ IDEA - Capable and Ergonomic IDE for JVM
Mochi - Write notes and flashcards with Markdown and study them with spaced repetition.
Embitz - Embitz is a free C/C++ IDE built to meet the most demanding needs of its users working in the field...
Markdown New Tab - Write notes in Markdown directly in the 'New Tab' page