I just got an A64 3000+ 939, A8V Deluxe, and a gig of RAM. Already had a 9800 Pro 128mb, 160gb WD HDD, and a DVD-ROM. For less than $450, my system went from fast to extremely fast
I previously had a Barton 2600 on the A7N8X-E Deluxe. The board was extremely kickass, but the Barton is a sad excuse for a processor compared to the A64. If nothing is tying you to the old Socket A architecture (price isn't one of these things, a Barton 3200 is more expensive than an A64 2800, and the A64 will run circles around it), *definitely* get an A64 CPU. And just so you know, Socket 939 supports dual core CPUs and dual channel memory. Socket 754 does not, and it's not a whole lot cheaper.
My only complaints about the A8V are the drivers (quite a few different ones to install, whereas the nForce drivers come in one tidy package), and its onboard audio. It is crap compared to nVidia's SoundStorm stuff. I mostly got this board because we sell it at the place I work, and it has an AGP slot for my good ol' 9800 Pro, which is still a very respectable card.
Audigy 2 sound cards give you *very* slightly better performance than SoundStorm according to the benchies; I highly recommend SoundStorm. It's extremely kickass
If you have an NF2 board, get the older 4.27 driver package (or any 4.xx I suppose. I used the 4.27 set). The audio drivers in the 5.xx packages suck ass (lots of bugs; in UT2004, many sound positions were screwed up, making it more difficult to play), and my system was overall slower with them.
FX series graphics cards have **terrible** PS 2.0 performance. Get a 6600 GT (maybe an ultra if the price is justified. if it's anywhere near a 6800GT in cost, jump for the 6800GT), or a 6800 GT/Ultra if you want nVidia (no non-GT/non-Ultra cards, they're a waste of money. GT cards are more cost-effective and can often be OC'd beyond Ultra speeds), or if you want ATI (they've improved their drivers quite a lot over the last two years, although I still favor nVidia's drivers... got the 9800 for free though, so what can I say
) the 9800 Pro (not the non-Pro, which has half the memory bandwidth! huge performance hit for that.), X700 (same performance class as the 9800, but PCI Express), or higher.
RAID5 isn't as fast as RAID0 unless you want to pay a premium for a good RAID card (with which I am not familiar, sorry), and even then it would still have slightly higher latencies (probably negligible) because of the math that the controller has to perform. RAID5 is more server-oriented, and does very well in those environments. If you need reliability *and* speed, RAID10 (aka RAID0+1) is a better option. Else, RAID0 on three drives... faaaast
So... dump everything you have but the hard drives (your RAM is too slow, get PC3200 or better), keep the case if you want, make sure your PSU is in good shape (if it's more than a year old, seriously consider replacing it; PSUs die horrible and often-catastrophic deaths), and either use the rest to build a low-end system to keep or sell, or sell the parts. Unless you can live with 4x DVD burning.
You'll end up spending anywhere from $500 to $900+.
MD-2389, the SB Live is Creative's budget card series. Of course they suck nuts.
I work at a computer store that sells a cheapo Live card in a white box for $27.
okay, I think that's everything...