As has been said before, there's no reason not to go with an i865 board. It would be $100 cheaper, and the only benefit of the i875 is CSA GB LAN. This is only a benefit if you have two machines with CSA and you like to throw 4GB DVD images around your LAN for the hell of it. The P4P800 is almost the same board for $94.
Do you REALLY want the Plextor that badly? Do you realize that those 1GB CDR's will NOT play back on other drives? It sounds like a major waste of money to me. You'd be better off spending $48.99 on the Lite-On 52x32x52x16x CD-RW/DVD combo drive. That Plextor is just a complete waste. It's $88.50, and for $89.99 you can get the NEC dual-layer DVD+R burner. You will eventually want a DVD burner, even if you want to wait until DVD-R dual-layer shows up in a few months, and then there will be no benefit to having 3 CD drives in your machine.
It looks like you've just decided that the most expensive US Robitics modem is the way to go. I've personally found that USR modems have gone downhill in a big way in the past few years. I've had no problems with any V.92 Conexant winmodems, which is more than I can say for 3COM/USR. The $9.50 Zonet modem on newegg ($12.50 with shipping) is a really good modem. If you're really planning on having dialup forever, then by all means go with a hardware controller, but I would hope this is a temporary thing. A winmodem isn't exactly going to tax a 3 GHz CPU.
Those Noisetaker PSU's are really nice, but you should get the $63.25 model of the 370W one instead. You don't seem to understand what Active PFC is. It is actually slightly more efficient to have no PFC. Read this:
http://www.dansdata.com/gz028.htm
I would go with OCZ Enhanced Latency memory. OCZ EL and Kingston HyperX are both the same timing, and are about 10% faster in many benchmarks than your average CL3 memory.
Is there a reason to spend $88 on an Audigy2? Sure, it's a great card, but do you have a home theater built around the computer? Do you have 7.1 speakers? Do you have acoustical foam on the ceiling and walls? Is this really going to sound any better than the Realtek 8-channel audio that's going on motherboards now?
The price of your list there is up to $1600 with shipping. I'm not going to give you a hard time about going with Intel, but I must say that you're not getting much computer for $1600. You're spending hundreds of dollars on the little things that you'll never notice.
Nobody needs a $1600 machine, do they? This is about bragging rights. For that price you could get a Socket 939 Athlon 64 which will actually be upgradable in the future. For almost the exact same price you could get:
Socket 939 Athlon 64 3500+ Newcastle Retail: $499
ASUS A8V K8T800 Pro, GB LAN, 8-channel audio, etc: $169
Sapphire Radeon 9800 Pro (with R360 core from 9800 XT): $210
2X 160GB Hitachi Deskstar 7K250: 2X $103.50
2X 512MB OCZ EL DDR400: 2X $128
Lite-On 52x32x52x16 combo drive: $48.99
Cooler Master Centurion 4 silver case: $64 + $15 shipping
Enemax Noisetaker P 370W: $63.25 + $6 shipping
Zonet V92 PCI modem: $9.50 + $3 shipping
Logitech Cordless MX Duo: $75 + $5 shipping
That's $1630.74, and it looks like your Intel system is just over $1600 with shipping.
The Raptor 74G is the fastest thing out there, but the Deskstar 7K250 is as fast as the Raptor 36G, and a 320GB RAID is probably better than a 74G single drive, but I suppose that depends on what you want. Maybe you want to save $7 and stick with the Raptor.
If you're going to go with Intel, that's great, but it doesn't mean you have to waste your money.