(Edit: sorry, like I said, I'm pretty fried. I'll read the FAQs first)
(Edit 2: okay, no longer sorry, the FAQ doesn't answer my question and the only link in it that might be related is a 404)

Hi, sorry if this comes off as incoherent, I was up all night working and could really use some shuteye.

IANAL, or a game dev, so I don't know how the legal stuff works. Let's say I come up with a great storyline, general design, and what I think is a killer title, the kind someone might be inclined to "borrow" if I'm not protected. Now, I really don't care if someone steals ideas from me. Imitation, flattery, and all that. Plus, I like my ideas, generally speaking, so I wouldn't mind seeing them realized, even if it's not me doing the realizing. I digress; I'm just trying to say that I'm not uptight about this kind of stuff, much less think anyone actually wants to swipe my ideas.

But I don't want to find out that I can't use my own ideas because someone used them first, either.

So, how would I "register" my work so I have it on record that it's original and not "derivative," to use the legalese.

Or, what if I come up with a title independently, only to find out its been used, but in an otherwise unrelated work (including video games)? The more I think about it, the more I suspect this could be the case - it's not a terribly original name, just an apt/catchy one.

You can register your copyright as soon as you commit your idea in tangible form (like writing, for instance). Go to copyright.gov if you're in the USA.
The name of the game and the characters are not copyrightable -- those would be subject to trademark instead.
You say one of the FAQ links is broken? Care to say which one?

Noticed that

http://archive.gamedev.net/reference/articles/article1985.asp

and

http://underdevelopmentlaw.com/clone-games-and-fan-games-legal-issues/

are broken ... so I did not find what I was looking for, either.

Basically the whole question: Q. What is the difference between Copyright, Trademark and Patent?

is arguably not answered at all right, right now.

Found the archived Gamedev article under a different URL, though:

http://www.gamedev.net/page/resources/_/business/business-and-law/legal-issues-for-rookie-development-studios-par-r1985

Part I is there:

http://www.gamedev.net/page/resources/_/business/business-and-law/legal-issues-for-rookie-development-studios-part-i-r1971

The underdevelopmentlaw website has been redesigned. I'm sure that article is still there somewhere. Until I find it, here's another: http://www.intelaw.com/pages/thb/articles/gamearticle2.htm

[Edit] Um, well, actually, underdevelopmentlaw is down completely. I don't know if the articles are going to be posted somewhere else or not. Anyone who wants to see those old articles could try the waybackmachine.