Motherboard & Crossfire (Newbie)

GIGABYTE GA-MA790X-UD4P

It's a very good price for a quality Crossfire motherboard. This one is cheaper, but I'd get the Gigabyte for $10 more: http://www.newegg.com/Product/Prod [...] 6813153129

Crossfire is expensive. You have to get a good MB and good PSU to support it. I would go for the Gigabyte board as well. You can try this board, but ASRock is a low quality manufacturer, its a risk I wouldn't want to take on a MB.
http://www.newegg.com/Product/Prod [...] 6813157139

Wattage isn't important, its Amperage and build quality. For 2 4830's, you want a PSU like these:
http://www.newegg.com/Product/Prod [...] k=ls%20550
http://www.newegg.com/Product/Prod [...] &Tpk=ea650
http://www.newegg.com/Product/Prod [...] 4&Tpk=550w <== My first pick
http://www.newegg.com/Product/Prod [...] 6817341010

Yep. Any of those PSU's would be good, you could run 2 4850's on the 550vx.

What type of ram should i get?

I dont want to spend too much on it!

The Gigabyte GA-MA790X-UD4P is probably the only 790X board with the SB750 which will let you overclock further if you upgrade to a phenom II CPU. If you want a cheaper board though, this is the cheapest one that will give you dual 8x PCI-E slots for crossfire

ASRock A780GXE $79.99
http://www.newegg.com/Product/Prod [...] 6813157139

It doesn't have the SB750, and uses the 780G chipset. It will let you upgrade to an AM3 CPU latter on and even supports 140W CPUs. Since the 780G was only intended to have a single 16x PCI-E slot, the 780G takes a page back from the AIT crossfire chipset X1600 (ALiveXFire-eSATA2)days and uses a small board to divide the lanes so that you can have two 8x PCI-E slots. Of course that old board used a switch card that had to be in the second slot for a single card while this new 780GXE uses a well placed switch card that stays out of the way. It even does external SATA the same way as the old ASRock ALiveXFire-eSATA2 board.