It really depends on what source you're using. If it uses MySQL, then I recommend MySQL Server Community Edition with MySQL Workbench (never install appserver). If it's written in C# using .NET Framework, then I recommend using Visual Studio. If you're using a source that's in .NET Core (like my most recent source is), then I'd recommend Visual Studio Code (great little code editor). I use the built-in Windows calculator a lot in Programmer mode for switching between decimal and hexadecimal. SageThumbs is nice for viewing dds files in the client as thumbnails in Windows Explorer. Paint.NET is also nice for editing dds files. You can download git if you like to save your code to a repository in the cloud. I can't think of much else.