Obviously with the first one I would have to get a Video Card but the 9800 GTX is the main reason the second combo is more expensive.
This is around what I would like to spend, with the whole build not being higher then ~$650. Is the 9800GTX good enough for GTA 4? I know how it loves to eat video memory and power (If i dropped in two for SLI). If I get the first combo, I am leaning towards the GTX 285 or the ATi 5750 but beyond that I would have to get a new power supply, which I just bought. Also, is the DDR3 Ram included in these combos good? all the OCZ products I have know work great (flash drive, DDR2) but what about this?