I am narrowing down to what chipset for the MB to get.  I am going to get an NF4 board with a veinus core CPU.  However, I was looking at ASUS A8N-E MB for around $125 and found a Chaintec VNF4 MB with the same physical specs (i.e. slots capacity) for $85.  The ASUS board seems to be for overclocking and tweeking, which I probably won't do, but is it a more stable board and better performer since it is considerably more expensive?

Yes, what GunnerMan said about ASUS's is very true - nice stable boards that tweak 'ok'. You might want to check out the range of AMD supported mobo brands here.  I support DFI LanParty - I don't find it very stable, but its loaded with nice geeky tweeky features!
Dan

Edit: If overlocking isn't a priority then you might want to consider getting a San Diego core - they don't OC as well becasue of a 1mb L2 cache, but will beat a Venice in games for the same reason. 

I have a ABIT AV8, you should look into it, its the OCer's heaven! 8)