AM2 motherboard help

[hahahax]

I already psoted in the monitor and vidcard sections, now I need help with my new motherboard

Here's what I'm currently getting..
AMD A64 X2 5200+ (2.6Ghz/Dual Core/2x1Mo/AM2/Retail) 149$
1024Mo DDR2 800Mhz PC2-6400 Gold OCZ (Spécial) 64.95$
1024Mo DDR2 800Mhz PC2-6400 Gold OCZ (Spécial) 64.95$
250Go WD 7200rpm SATA2 16Mo (WD2500KS) 74.95$
Vid Card: Either a 1950pro or a 7900.. maybe a 8600gt but i was told to stay away from them.

I don't know anythign about mobos..
What's the difference between these? and with my current hardware, which one would be best and why?
ASUS M2N-MX(GF6100,Audio,Sata II,GLan,PCI-E, Video, Dual DDR2) 83.95$
ASUS M2N4-SLI (NF4SLI,Audio,Sata II,GLan, Dual PCI-E,Dual DDR2) 104$
ASUS M2N-E (NF570 ULTRA,Audio,Sata II,GLan,PCI-E,Dual DDR2) 113$
ASUS M2N-SLI-DX (NF570SLI,Audio,Sata II,GLan, Dual PCI-E,Dual DDR2) 155$


Thanks a lot.