Here is my list of recommended tools:

• SlickEdit : A commercial editor that will make a massive improvement in your productivity!
• Ikalogic ScanaPLUS logic analyzer : A great value-for-money multi-platform logic analyzer with a multitude of protocol decoders (UART, I2C, SPI, LIN, CAN, 1-Wire, ...) that is essential for rapid driver development and debugging. Once you start using a logic analyzer, you will realise the insanity of driver development "in the dark" and kick yourself for wasting so much time before!
• UnixShellUtils : a minimal collection of Unix Shell utilities (make, sh, echo, rm, etc.) and other utilities (SRecord) used to build projects using advanced Make scripts.
• Tera Term : Free terminal emulation software to interact with CLI applications and upload new firmware via bootloader using XMODEM-CRC protocol.
• 7-Zip : a file archiver with a high compression ratio.
• Tortoise SVN : a Microsoft Windows Explorer GUI plugin for Subversion (a free version control system that manages file and directory changes over time).
• Doxygen : a tool that generates documentation from source code.
• Atmel Studio : an Integrated Development Environment (IDE) for developing and debugging Atmel ARM Cortex and AVR microcontroller applications on the Microsoft Windows operating system. It includes the GNU GCC build toolchain for C and C++.
• MSYS2 : a collection of GNU utilities such as bash, make, gawk and grep to allow building of applications and programs which depend on traditionally Unix tools to be present. Note that a minimal set is provided with UnixShellUtils.
• FTDI USB to serial converter tools:
  • FTDI FT230XS USB-UART Bridge Virtual Com Port (VCP) driver
  • FTDI FT_PROG EEPROM Programming Utility : an EEPROM programming utility to modify EEPROM contents (including settings like device descriptors, pin configurations, ...) of FTDI devices.
  • FTDI CDM Uninstaller : Uninstaller to remove old drivers.
  • FTDI Ignore Hardware Serial Number Registry Editor Utility : a utility that edits the Windows registry to ensure the serial number descriptor of each FTDI device is ignored during driver installation. This feature ensures any FTDI device connected to a USB port is given the same COM port number.