What to design for

Ok... The eve of Ati... err AMD releasing their new almighty HD2900xt and I have second thoughts of my wait for this card. I want to get a system with the Hd2900xtx over clocked edition because it can do double the bandwidth of the 8800gtx. Saying that, I have seem the 8800gtx and it is beautiful. I can also get one of these now if I want to. I am building a new computer after the Intel price cuts that should take place starting the 22nd of April 2007(if I am correct). Should I design my computer for SLI or Crossfire? Should I just buy a good motherboard that can take advantage of the core 2 duo and not care what chipset it is? I am so confused now.....

So... Ati design, design Nvidia design, best mobo for C2D (and one video card)....

I have particular budget. I have more of a time restriction. I am giving my computer to my brother for his birthday and I will not have a computer after that. His b-day is the may 5th so i am looking to buy at the end of this month. I do not want to spend more the $2,500. Right now the rig I have designed is $2,400 with everything on it. I am expecting to see a little drop in price at the end of this month.

This is the system so far:

from newegg.com
GIGABYTE 3D Aurora 570
EVGA 122-CK-NF68-T1 LGA 775 NVIDIA nForce 680i SLI
BFG Tech BFGR88768GTXOC2E GeForce 8800GTX
Thermaltake W0106RU 12V 2.2 & EPS 12V version 700W Power Supply
Intel Core 2 Duo E6600 Conroe 2.4GHz LGA 775
G.SKILL 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 ( x2)
SABRENT CRW-UINB 52-in-1 USB 2.0 Internal Card Reader w/ USB 2.0
NEC Black 1.44MB 3.5" Internal Floppy Drive
Western Digital Caviar RE WD1600YS 160GB 7200 RPM SATA 3.0Gb/s (x2)
SAMSUNG 206BW Black 20" 2 ms (GTG) DVI Widescreen LCD Monitor
ASUS Dual Panel Black and Beige ATAPI/E-IDE DVD-ROM Drive Model DVD-E616A3
ASUS 16X DVD±R DVD Burner with 12X DVD-RAM Write, LightScribe Technology IDE
Creative 70SB046A00000 7.1 Channels PCI Interface Sound Blaster X-Fi XtremeGamer Fatal1ty Professional Series

from xoxide.com:
Sunbeam / Tuniq T-120 CPU Cooler
Thermaltake Thunderblade 120mm LED Fan (Blue) (x3)

what do you think? I am willing to switch out the mobo with the Intel BX2 if i decide to go crossfire.....