SCM Draft 2: The best editor currently, and probably forever, if SC2 comes out when they plan it, SCM Draft has the best terraining work, including copy/paste, it allows you to choose between text and classic trigedit, now has the sprite functionality of StarForge and can basically do everything any other editor can do and more.

Starforge has its abilities to input any data, but that's for the most part useless.

UnKnown Edit: The only map editor for Macs. Still in works. Trigger exporting, units, terrain.

Staredit mods (like X-tra Editor 2.6/FartyEdit) can be useful, since they're pretty stable and can save/load triggers.

Starforge:Ultimate has reached a plateau and hasn't really been updated in a while.

Notepad++ and either MacroTriggers or ProTRG: Both are basically compilers for triggers, MacroTriggers is it's own language with documentation, ProTRG is built on Python. MacroTriggers is cleaner looking, but isn't supported any more and lacks a few useful features, and ProTRG is definitely the best choice for anything complex. Basically, these allow you to easily duplicate triggers using arrays and variables and loops and make your mapping experience less of a brute-forcing experience, and more of a problem solving intensive job. Notepad++ is the text editor through which both of them are made to run, and the compiled triggers are put into SCM Draft's text trigger format.

TinyMap2: For compression when you're finished, by far the best compressor, and just as an unintentional side-effect, it also happens to stop basically all unprotectors out right now. If it glitches on your map, switch back to TinyMap.

DatEdit: A modding program that comes in handy as a reference sheet for SC unit's properties, things like weapons range, vision range, attack speed, and other useful information can be obtained from it.

PColor: Only truly useful if you're going for some of the funky player colors, lets you preview what certain player colors look like so you can easily pick one.

Falkoner's Terrain Compilation: If you're going to do any major terraining, having a huge selection of blends to pick from is very useful, this compilation I made a while back has maps for every tileset that show different terrain blends, for easy copy/pasting into a map.

SC Map Importer/Exporter (SCMIE) A very convenient tool that lets you transfer just about anything from one map to another.

IrfanView (freeware program) or Zamzar (website requiring an eMail account) can be used to view and/or convert .pcx files to other image formats.

If you have a suggestion what program should be on that list too, briefly explain to me why it's useful and provide a download link if possible.

I just uploaded the Location Hack to the DLDB, I figure it's not much of a hack, so might as well try it.

I guess if Falk Compilation is in there, my Brush Project can also be listed.

PROEdit / SCMIE source
Ruby Wrappers for Trigedit generation
Trigger Sorter

these should probably be moved to this forum at least, even if they're not linked in this topic

Probably should've included:
MapExp: A useful online program hosted by Farty that will generate a minimap preview of your map and give detailed information(change print settings to Print(some) labels) regarding your maps stats, an offline alternative that's slightly more buggy would be MapStats.

W-Mode: A useful hack that doesn't affect SC's innards at all, so it's undetectable my Blizzard, but it places SC in a window, allowing for easy access to testing without having to wait for SC to load while you maximize and minimize it.

If not the Windowed Mode utility, at least the Stats utils.

I had them included in the first draft, but then decided I don't want any program in existence (someone is bound to find it useful) to be on the recommended list in the opening post.
The more common ones make it to the OP and the maybe-useful-in-a-specific-situation ones can reside in the following posts.

UnKnown Edit: The only map editor for Macs. Still in works. Trigger exporting, units, terrain.

What's the best program for taking pictures while testing your map? So you can post screen shots of Interesting places or events?

Quote from alaska

What's the best program for taking pictures while testing your map? So you can post screen shots of Interesting places or events?

Press Print Screen, and SC will take a screenshot for you. The pictures it takes are also pretty high res too, so you don't have to worry about the quality

Ok, it saves as a pcx, what program can I use to veiw these pictures? I'm using Windows 7. Just change the extension?

No no no. You can use GIMP 2, IrfanView, PaintShop Pro, or Adobe Photoshop to view and convert .pcx images into .jpg and .gif images, amongst other things. The first two in that list are freeware.

If you don't want to download a program to convert files, you can convert pcx files online by going to zamzar.com

Quote from Pr0nogo

.jpg and .gif images

Use PNG. jpg is terrible, and gif is less than good.

If necessary I can make something to convert pcx to png.

Quote from O)FaRTy1billion

Quote from Pr0nogo

.jpg and .gif images

Use PNG. jpg is terrible, and gif is less than good.

If necessary I can make something to convert pcx to png.

.GIFs are actually pretty nice, particularly for SC1, as both the game and the format are 256 colors. Unless there is something else that I do not know.

I was originally going to say that both .jpg and gif were terrible ... but then thought of the same thing. My post was mostly promoting png, which is generally better than gif. I just tested on a random screenshot and the pcx was about 300KB (about the same size as the 8-bit bmp ...), the gif was about 150KB, and the png (8-bit) was about 100KB.

gif is fine for sc.
png is the same except with standard settings it produces bigger file sizes than .gif. However if you're using a program that can save palette based png's the resulting file will be a little smaller than the .gif.
Quality stays the same in all 3 formats.

Quality sucks in jpg. Also I don't know of not being able to save 8-bit png.