If you have $3000 to spend, spend $3000. You can always build a nice raid array... gold plated heatsinks... uhh.... diamond incrusted gpu cores..? I take that back, don't spend $3000 on a computer. $2000 is plently.
If he is asking for an FX, I would expect the $3k to available and burning a hole in his pocket. Between the FX and a high quality screen, mouse, keyboard, and speakers, he can easily burn more than half of his budget. A pair of 7900GTs and hes down to $6-700 available for mobo, memory, case, PSU, HDD, optical, etc. Don't forget $200 for XP...
Hes not looking for a tower, hes looking for a complete system, big difference.
3k is ample for a complete system, I'd use the whole budget.
I'd also wait a bit for Conroe to rear its head so you could gauge your options a bit better, but you could knock out everything but the CPU/Mobo, parts-wise.
Have you considered ordering an OEM PC? Companies like Velocity Micro and Maingear make excellent gaming-rigs. Might be something to investigate if you don't want to/aren't comfortable with building (you didn't say in your post, so...)
^wow same build I was imagining for myself, 454Casull, except for I would probably prefer a Lian Li 7B Plus II, a 500GB Seagate HDD and that ~$700 NEC 20.1" WS LCD.
The Viewsonic is more budget friendly though haha. Do you guys think that Core 2 Duo will be that price when it first comes out? I remember when Newegg first had the X2 3800+ (which was supposed to be around the $300 range at that time) but they were selling them for $400+ My OC'd Opteron 146 should last me until C2D drops in price and there are more mobos for it.
I would do what everyone else is saying and wait for C2D. Even if you don't want to buy Intel, prices on AM2 will probably drop to compete w/ C2D later this summer. You can also get an X-fi and some extras like round cables + silent fans if you want to spend all of your budget. $3k seems like a lot but its a good investment.
are you wanting to build this yourself? or get a prebuilt system.. if you're wanting to spend that much it might be worth it to just get a prebuilt.. but who knows..