There are no major flaws, but if you're going to build a PC for gaming and want the best bang-buck ratio, you'd be better off with an AMD system. Not that I dislike Intel, just because widespread knowledge establishes that AMD will provide you with better gaming performance for the same price. Still, sticking to Intel, I'd suggest a mobo based on the 915 or 925 chipset for socket 775, as it has a brighter future than a i865-based mobo and you can go with a PCI Express video card (unless you plan to use an AGP card you already have). If you want to stick to your Intel socket 478 plan, you'd be better served with a i875P-based mobo performance-wise. That said, the budget you're on would help us determine better what can be further suggested.
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<font color=blue>DFI NF2 Ultra Infinity
XP3200+
HyperX PC3500 1Gb
Sapphire 9600XT 256Mb
Antec True 480W
2X Seagate SATA 80Gb Raid0; 1X Seagate UATA 40Gb
LG DVD-ROM; LiteOn CD-RW</font color=blue>