Wow, thanks for the info guys! I'll start answering person by person.
I've never really used mindmaps but I can see the great advantages in them, I might start using them for the initial planning stages when I setup the different variables (like what powerups for this ship etc.). Freeplane looks good, I'll give that a go.
I also have only ever done normal fiction writing for my games story, but it's always had its problems and incorporating the different people have sometimes made it hard to understand. Screenplay writing would be far more beneficial, not to mention I can separate lines with info on how to proceed without confusing the story, that'll be a great help indeed. I don't like using storyboards as I prefer to keep what it looks like in my head and to convey that to any artist I might collaborate with or myself in order to make those thoughts come to life. I prefer my imagination to sort of create and re-create what's going to happen rather then get something permanent set down. I'm not sure if that's such a great idea in larger projects though, so I'll have to have a think about it. I'll check out the link later.
Also, I had a look at Celtx, but I don't feel the subscription is worth it when I can do the same thing with a bit of time and effort.
I used to use One Note all the time, however I never thought about using it for game design. its free-form ability can certainly be useful, it might be a great way to collaborate all my notes and work into one area.
I don't understand, did you misunderstand what I was asking? Or am I misunderstanding you? Wireframes can certainly be useful to get an idea or multiple ideas running, but I'm looking for what's useful once you have your idea and are designing it. So in essence, I would be the designer in your comment.
Everyone who actually works in the industry understands the difference between the design and the development, unfortunately google and most people who aren't don't understand it. That's why it was difficult to allocate any substantial information on the matter.
Additionally, I was looking for software that would help me design games, regardless of such things such as what the company needs to look at. I'm not up to, or anywhere near, the stage where I would be pitching my game to a company, so the only thing I'd be looking at right now is what I need to create the genre of game I'm in. Which you're right, it depends on what I'm creating. Which means everything people are telling me about will be useful in one way or another.
I believe that's it, thanks guys! This is really invaluable help.
If, at any point, what I post is hard to understand, tell me. I am bad at projecting my thoughts into real words, so I appreciate the knowledge that I need to edit my post.
I am not a professional writer, nor a professional game designer. Please, understand that everything you read is simply an opinion of mind and should not, at any point in time, be taken as a credible answer unless validated by others.