Goamins frae Scotland!

[Cobra!]

I'm not an expert on graphics cards but unless it is a model that just came out, most AMD and NVidia cards will work.  Extremely new models might not have Linux support right away.

That makes sense, I suppose, is there any Linux support for a GeForce Titan, or the AMD equivalent?

One thing to be aware of is that most (if not all) new motherboards these days will come with UEFI firmware instead of the old BIOS firmware that everyone is used to.  UEFI firmware typically allows for booting and installation in either UEFI mode or BIOS/Legacy mode.  Currently Linux Lite does not support installation in UEFI mode.  So if you're going to install LL, go into UEFI settings and make sure it is set to BIOS/Legacy/CSM mode.  (Wording may be slightly different from one manufacturer to the next, but should be something along those lines.)

That sounds worrying, but it's seems like a bridge I can only cross when I come to it. So what's the difference between UEFI and BIOS? Is it crucial to making a gaming PC? Does it make a difference to performance?

If you're planning to put Windows 8 on the new computer, get a "retail" version of it.  The retail version will allow you to install it in either BIOS or UEFI mode.  I don't know for sure, but think the "OEM" version may only install in UEFI mode.  Install Windows first, then install LL and any other OSs you want on the machine.  For best results, all OSs that you put on the computer should be installed using the same mode.

Just as well that was my plan from the start, then! I was planning on installing my modern Windows OS for newer games that don't work on WINE, then install Linux Lite to use as my main/everyday OS, and maybe install AROS for Amiga games, OSx86 for Mac programs/games, and FreeBSD, basically, every OS type available! I was thinking of also installing legacy Windows, such as ME and XP for games that don't work on Windows 7/8/9 or WINE. Do you think all this would be possible to do with one machine?