The editor I use is called vim.
Supports syntax highlighting for those and 200 other languages, and is incredibly fast to use. In my work as a programmer and sysadmin, I spend about 90% of my day in vim, and I wouldn't use any other editor. (I have also used MS Visual Studio in the past, before I learned vim.) There is a bit of a learning curve, but once you master it it will be your favorite tool. It is Open Source, Free (as in speech) and runs on almost every operating system.
It can do automatic completion of keywords, and much more with the many plugins that are available for it.
There's a short feature summary here: