I'm almost totally new to Linux (a fact that will soon become horribly apparent, I'm sure), so please don't flame me for this one.

I have only a little experience with Linux on my own (installed Red Hat 6 and 7.3 once each, did almost nothing beyond that), but I'm looking to TRY to move as far away from MS as I can. With that in mind, I want to build a box exclusively for Linux work, so I can get a feel for the thing without endangering anyone. Here we come to the reason for my post; I've been trying very hard to figure out whether or not my preffered hardware will work, and I've found it difficult to get the stories to match up, or even make sense to my poor Windows-ish head. This is really my last-ditch attempt to find out what's gonna work and what won't.

Btw (proving I know SOMETHING), I'm aware that different versions often support different hardware, I'm willing to change the load if it'll get my hardware working (small budget). Here's the plan:

-Motherboard, CPU, RAM: Haven't decided yet, but it must be CHEAP. All who wish to offer suggestions, please do so.
-Video: NVidia GeForce2 MX400 (I was able to find plenty of info on this, but I thought I'd list it anyway)
-Sound: I've read that the old Ensoniq cards work well, so I was thinking of throwing one of those in (as you might have guessed, I already have one).
-Network: Realtek 8139D PCI (I swear by this chip, so I'm hoping I can use it here too).
-HD: 40GB Maxtor, if that's enough space to start out with.
-DVD: Lite-on 16x. They're cheap, I love them, and I kinda already have one.

For now, that's all I've got (I'm not worrying about anything else right now). Assuming I can figure out the mobo, that's enough to get the thing running at least. The mobo is my really big problem, a previous experience has me afraid that I'll get an unsupported or only partially supported chipset. Since that dictates my CPU and RAM, I'm kinda stuck.

Anyway, any help you guys have the patience to offer will be greatly appreciated. Think of it this way; you help me, and I become another Linux-lover (I'm already a devout MS hater). Thanks.

If your question is hardware compatibility, then all your hardware is acceptable (I think, you may want to check Hardware Compatibility List - HCL for the distro you want) . Of course the M/B should be the main issue. But investing in known brands like ASUS and QDI pays off in the long run.

As for the MS hater thing, drop it...
It's better being for Linux than against something else (eg MS)

Mostly I'm not sure about which CPU to go with. If I could find a good Socket7 mobo I'd just use an old K6-2, but that's not really an option any more, so I'm not sure if I want a Celeron or a Duron. And regardless of that, should I go with a VIA chipset, or is it safe to get something else, like an old NForce or Intel?

Oh come on, it's so much fun to hate things...

Celeron or Duron dont matter much , but dont expect to see linux in its full potential. (That from a guy running linux happily in his really old Pentium II @300Mhz). My experience says kepp off those VIA chipsets. Anything is better than that. So ... Good Luck with everything!