OK, let me start this entry by saying I don't really like discussing the various softwares and skills required for game development. For the most part, they're simply tools: a means to an end. I consider ideas far more important than the processes that those ideas go through to become actually playable games. Unfortunately, this is not so in the games industry itself.
There are three basic routes into the industry, ignoring lateral switches from non-game-development related fields for the moment: become a seasoned programmer (either through a university degree or plenty of demonstrable coding experience), become a seasoned graphical artist (same way as programmer: either through a degree course and/or with an impressive and extensive portfolio) or become a designer after years of playtesting experience (since you'll eventually get an idea of how both games and the games industry work). I, perhaps unfortunately, believed that the third field of games development - Design - could be entered the same way: degree course or portfolio. This is not necessarily the case however, as the design role is still very much undefined as far as the skills required for the role are concerned.
Basically, a designer needs to know games: How they work, why some sell better than others, what people look for in games, enough knowledge about existing games to come up with something different for a new one, etc. So there needs to be that sort of media studies edge to it (though an unsurprising amount of it is common sense). A designer also needs to know enough about the coding and art aspects of game development in order to properly synergise with those respective departments, not to mention that a game designer will be frequently in the position where they make their own levels, which will require a knowledge of both scripting (coding's little brother) and molding the level itself (which is kind of arty, though a designer's level will end up looking fairly primitive graphically until the art guys fill it in). Also, most importantly, designers need to be highly literate both verbally and on paper if people are going to need to figure out what they're talking about.
The designer role is still sort of new; previously, any senior programmer or artist would be the one required to figure out how the game would play, and then assign the tasks to their underlings in those two areas. Smaller companies still do this for the most part. Having a separate staff for a Designer group means the artists and programmers simply do as their told in terms of how a game will work (though obviously will be quick to point out to the designers what can and cannot be done within the existing budget).
So, technical skills to be a designer, based on what I've learned through either succeeding with an interview (which I've done once) or failing an interview (which has happened, um, more than once):
* High level of literacy.
* High level of verbal communication.
* Scripting knowledge/experience (would be very wise to have some proof of this)
* 3D Graphics knowledge/experience (see above)
* A degree (surprisingly unnecessary)
* A lot of testing experience (beneficial from what I've learned from designer peers)
* Plenty of mod levels, made with something like UnrealEd (*important*, since this is what you'll be doing a lot of)
You can gleam the same kind of information from any "how to be a game designer" site, but I'm telling you as one of those people who have suffered over the past few years in trying to get somewhere in this field: You need to prove that you're better at this stuff than the hundreds of people like me applying for the same job. Once you've got a couple of design gigs under your belt it gets a lot easier (so I've been told), but the first few jobs are highly critical.
If all else fails, be a graphic designer or programmer (either inside the industry or out) and switch to games design. Even if you know barely anything about how to make a game, they'll probably accept you for your related expertise alone.
Just a quick note here: I haven't actually mentioned any software by name that you should be using. This is simply because software comes and goes into and out of fashion. You'll rarely use the exact same piece of software twice, especially when you consider a lot of companies have their own "in-house" modifications of existing software. Just try everything: play around with software until you've got the hang of it, maybe make some small thing to prove as much, and then move onto something else. Try all the programming languages, don't just stick with one. Ditto with graphical tools, paint programs, level-creating mods and even music programs. Even if something's old and outdated, tinker around with it and add it to the list of tools you know how to use. Employers need to know that you can quickly get to grips with whatever tools the job will throw at you, so no piece of software you learn will be entirely useless to you.
OK, to wrap this up, don't take my word entirely as gospel but keep it in mind. There are plenty of excellent designers who have made it giving out similar advice elsewhere. But they're no longer where you are now, and they've probably forgotten that it was partly luck that landed them their first real design job. So for all you would-be designers out there, good luck, and don't you dare apply for any of the same jobs I'm applying for. Or I'll kill you with fire.
