Surely you won't require Sli, so the ASUS M2N-E should be the better & cheaper option.
Between the graphics card, I'd go for the 2400 PRO. 512Mb on a 7300GT seems a waste & not worth the premium - is it a lot?
As they're cheaper too, the Kingston RAM & ThermalTake TR2 420W PSU would do fine.
So my choices would be:
* ASUS M2N-E nF570 Socket AM2 Motherboard
* AMD Athlon 64 X2 Dual Core 4200+ 2.20GHz AM2)
* ATi Radeon HD 2400 PRO 256MB Support#1GB PCI-E
* Kingston 2GB Value RAM DDR2 667MHz PC5300 memory
* ThermalTake TR2 420W Black Silent+ATX 12V 2.0 PSU,20pin+4pin SATA ready.
If you're not gaming at all (except Windows own games), save more by getting a motherboard with integrated graphics & drop the dedicated GPU. G