Need advice on new system components & distro pick

I am a fairly experienced computer user who has
a pretty old system right now (486/120). I am operating
in Win 98 right now, and would like to learn about
programming and generally get more in-depth computer knowledge (especially Unix-type stuff). From what I can tell, Linux (or another flavor of Unix) is probably the best place to learn programming, since so much of the Windows stuff is "Visual"-based. Also I guess Linux will be good because a familiarity with Unix may be helpful. I also think that I'll probably learn more in a command-line environment, as opposed to a GUI (not that I'll never use X-Windows, I just don't want to rely on it). Based on this, which distribution should I get? I'm figuring on picking between Mandrake, Suse, Debian, & Redhat. I know that I can download at least some of these for free, but I'd prefer to have CD's in hand, plus the book that should come with a package. Also, at least a few of these distributions
come in two versions (Home vs. Professional, or whatever). My instinct is to get the cheap version and then download whatever else I need, whether it be compilers or whatever.

Ok, the second problem is my system. I am wanting to start mostly over (I have an almost new Western Digital 40 Gig 7200 rpm HD that I'll reuse, plus my 15" monitor). I am looking to buy pretty much everything else new.
As far as Linux vs. Windows is concerned, I am looking at buying the TriOS, detailed on this website

http://www.romtecusa.com/

Pretty much it's a hard drive switch, so that I can have Win XP (looking to upgrade that, too) on my first drive, and Linux on my second drive, and they'll never see each other. I know that I can dual boot onto one hard drive, but
I've heard quite a few things about Windows screwing up the Linux partitions, or Linux screwing up Windows. I could deal with these problems in the interests
of learning, but my wife will be using the computer for work, and if Windows screwed up, she would wig out.

As far as the rest of the hardware, I've been scouring the different hardware sites out there for the past two or three weeks, in addition to the Linux sites, to figure out what will work (I know Linux is picky...so I've tried to be careful).

Motherboard: Abit KR7A (no RAID, no ATA 133, based on VIA KT266A chipset)
CPU: AMD Athlon XP 1700+ (will probably buy an AMD approved heatsink/cooler along with it).
Video Card: Asus 8200 Pure T2 (Asus board based on NVidia GeForce3, Ti200, w/o extra software & stuff)
Sound Card: SB Live XGamer 5.1 (I know the 5.1 won't help in Linux, and I'm only getting the XGamer version because it's cheaper to get those particular games this way).
Hard Drive: 40 Gig, 7200 rpm, not sure of manufacturer (I've always used Western Digital, but lots of places seem to like the IBM Deskstar series).
RAM: Brand name, 512 MB, PC2100 DDR SDRAM, CL=2.0 if I can get it
Cable Modem: It seems like AT&T Broadband High Speed Internet on cable modem is the way to go in Jax. Looking at D-Link DCM100 ext. cable modem, two-way DOCSIS 1.0 certified, says it supports Unix "and other popular operating systems)
Network Card: Have no preference, will probably get something that claims Linux support
CD-RW: Not sure what to get (looking for <$100 & Linux compliant, of course), Acer seems to have some inexpensive ones out there.
Case: Mid to Full tower, looking for nice case. I'll be looking at computer show this weekend. Looking for 400W AMD approved power supply.

Well, sorry my post was so long, but I've been trying to nail down this information for the past two weeks, and it is extremely hard to weigh these options without prior first
hand knowledge. I'll likely buy a case this weekend at the computer show, but I'll be ordering the rest from a few internet sites over the weekend (been checking prices and
merchant ratings at pricegrabber.com, and I'll probably stop by BBBonline before I order).

If you have any suggestions on hardware or Linux distributions, I'd love to hear them. If you think that any of my assumptions are incorrect (about hardware, programming, etc.), please tell me so that I won't proceed in ignorance. As you've probably guessed, this computer will be spending some time playing FPS's & RPG's in Windows, but I'd like to have as much of the hardware function in Linux as possible.

Thanks,

Richard Mathews