I'm building a new PC.

I've had these components for awhile:
Phenom X4 9950 Black AM2+ 2.6ghz (quad, 64-bit)
OCZ DDR2 PC2 6400 RAM
Seagate 10k SATA HDD
500w PSU

I just bought:
Asus M3A78-CM Motherboard
LG 22X DVD-RW SATA

I'm going to install Win7 64-bit.

I bought a used video card awhile back, Saphire Radeon x800 Pro, PCI-E, that I was planning to use, but I was wondering if there is anything currently available for about $50 that would be better?
I believe this card is 256mb of DDR3 memory.
I saw this one:
Sparkle GeForce 8400 GS Video Card - 512MB DDR2, PCI Express
with 512mb for $40

or this one:
EVGA GeForce 9500 GT Video Card - 1GB DDR2, PCI Express 2.0
with 1gb!! for $70

how does the DDR2 compare to the DDR3?

I want to be able to run Need for Speed - Shift.
minimum requirements are:
AMD x2 3600 or better
video card 256mb or better

do I need to upgrade? (I'd prefer to be above the minimum)