It is always a headache to choose right microcontroller for your project, but even bigger one when talking of tools. In most cases chip manufacturers produce a proper tool to develop, debug and flash them. Anyway they aren’t cheap and open enough. Free versions usually are limited in code size or functionality. If you want free and unlimited solution, then no doubt, open source tools is your next choice.
But problem is that open tools may seem quite a tricky to start with. You must be familiar with command line specifics and it takes a bit of preparation before you can enjoy the development. Installing compiler alone isn’t the end. You also need makefiles, startup files in order to build source. This already sounds pretty nerdy. But hey, once you get one tool running, other will be a piece of cake. uCtools by Eric Evenchick introduces you to fast easy and concentrated start to most popular open source tools for microcontrollers. He has prepared makefiles, and instructions how to set up a particular tool on Ubuntu and gave a simple C program to start with. This is great resource for those who decide to use open stuff. So far there are templates for AVR, MSP430, Stellaris ARM, and Stm32L1. The list should go on eventually.