Alright! I made sure to have a look at all of these. I hope everyone who votes downloads and tries them all because you never know which ones you like in there that may not have had much forum publicity leading up to the deadline. I'll say something about each of them:

Terrain Deformer: Nice idea, but it really lacks polish, and to be honest I just couldn't get it to work. I mean, it would compile and everything, but including an executable would be nice. And I couldn't get terrain to deform. Sorry -- I didn't spend a lot of time on it -- I see its usefulness, and perhaps it works better than I could figure out, but even if it did it wouldn't be my first choice.
EDIT: This was an A8 issue. See post below for Widi's A8 version, and below that for my thoughts having tried the working version.

Particle Effect Builder: Very fancy effect builder. Lots of nice options. Great polish, and nice tutorials.

LBGUI: My favourite at the moment. Absolutely ridiculously useful, very customizable. Love how they function like their Windows equivalents, but completely customizable appearance. That's exactly what people expect in games. It feels like it should be integrated into GS. The only downside is that Conitec might be making it redundant in the near future with an official GUI dll, but who knows when that will ever happen. Bonus points for including examples. Plus, that's a ridiculous amount of code in there!

DialogED: Great polish. Appears very useful, but the manual implies that it will only produce C-Script. Big negative points for me, I'm afraid, as C-Script is only supported for legacy reasons now.

Light Frog: Beautiful shaders. A nice-looking light-focused alternative to Shade-C for those who don't want to write their own shaders. I like to write my own shaders, but that has no bearing on my vote here, as I also want good shader work to get due attention: this is high up there on my list. Bonus points for beautiful exe examples.

GS Updater: Very cool tool! Good thinking. I hope a lot of people get good use of it, and I hope everyone tries it, because as far as I know I haven't seen this tool get any attention prior to this actual contest. It's a gem, and I hope it gets at least a few votes.

FXED: Solid tool. I might start using it as a .fx editor. I think I already said a lot about it in the Projects thread. This deserves some votes too, or a prize.

Act: An example would've been very helpful, as well as some documentation. From what I've seen in Projects, though, this is quite a useful tool. Unfortunately with no documentation or example I can't really say much about it.

Particle Generator: Poor English, for one thing, made it difficult to use. Sorry, I know it's hard if English isn't your first language, but it's still pretty confusing to use. Not as polished as the other particle editor. Doesn't seem to offer as many options.

Multiplayer Scoreboard & 3D Entity Panels: I'll talk about both of them together, since they're both from EvilSOB. Now, EvilSOB deserves something for his pro-active help and great contributions in this community. And these are two solid contributions. I just don't think either are the most useful entry in this contest. My favourite is 3D Entity Panels, since it's just plain clever. None of the buttons in the example worked for me, however. And the compass rotates the wrong way when the player rotates. Bonus points for including an example anyway.

Well done to everyone who entered, though. I see a lot of effort in all the tools.

Jibb