I've got things minimally working in Scite... and a quick browse tells me that there is an Eclipse plugin and several other standalone editors, in addition to other general purpose editors with Lua capability.
Out of that, what do people recommend? Particularly, what do people who program primarily in Lua like to use?
Edit: Thanks for all the answers!
Most Lua users seem to use $TEXT_EDITOR_OF_CHOICE. There's a particularly nice Emacs mode, with all the typical Emacs goodies: REPL, documentation lookup, jump-to-error, etc.
There do appear to be a couple Lua-focused IDEs if you're on the Windows side of things: LuaEdit, LuaIDE. Also, Zeus is scriptable in Lua, which may help reduce mental context-switching.
Bah. I just use SciTE, like I do for most other programming tasks.
Then again, I rarely do big Lua programs, so I haven't used a true debugger yet (only simple traces).
There aren't so much debuggers for Lua anyway, even though there were severals tentatives in the field (including for remote debugging).
You can also do searches in the Lua mailing list, it is an excellent source of information. I recall a couple of IDE and debugging tools announced there.
I've been surprised by the lack of good Lua IDE. At the same time, I've been surprised by the lack of the need for an IDE.
In other words, you will come long with just a syntax highlighting editor and your own app / command line.
This applies to debugger support, as well. Getting full stack traces takes most need of a debugger away.
Lua Studio is actually nice: http://lua-studio.luaforge.net/.
I would like to see a good lua plugin for Visual Studio, most of them (if not all) doesn't work on Visual Studio 2008, that's pity.
I use LuaEclipse. It is a bit underdeveloped at the moment, but I've just got used to Eclipse. My colleagues use KDevelop (we're on Linux).
If you're on Windows, try Lua for Windows package (SciTE-based). There is also commercial editor called Decoda.
For Windows, there's a package named LuaForWindows which includes a version of SciTE that's optimized for developing in Lua and even provides a built in debugger.
I did a lot of programs for projecteuler with it.
Decoda is awesome if you're building using VC++ because it allows you to select the PDB of your program and then can launch your C++ program itself (with command line arguments and the working directory set to whatever) and then let you set break points and do stuff from within Lua code, as well as inspect variables.
I bought it awhile back and have been really satisfied with it; the only thing that would be more convenient is if it was integrated with Visual Studio.
I'd like to point out your attention at the excellent small editor named CodeMAX, I am not pointing you at the editor's website (http://codemax.luaforge.net/) because it seems that it is a little bit behind on the versions. Although the core is written in Delphi, it uses Lua for most things. Plugins, macros you name it. It comes loaded with the following plugins that have been created by the author:
Currently it is at version 1.1.9 and runs really lightweight and stable. I definately recommend using it for Lua coding. If you encounter any problem at all the author has always been really polite and strives to solve any problems that may arise.