Mobo for Phenom II X3 720 BE

The AM3 Phenom II CPU's (like your Phenom IIX3 720 BE) is backwards compatible with AM2+ Motherboards so it will run on both types of motherboards.AM2+ motherboards use the slower DDR2 RAM and the AM3 motherboards use the new DDR3 type RAM memory.If you absolutely must have 2 graphics card slots for ATI graphics cards the motherboards with the 790X,790GX or the 790FX chipsets are the ones you desire.The 790X ones are like the 790GX versions except that the GX version has onboard Integrated Graphics which can be disabled.Both 790X and 790GX chipset motherboards will run 1 graphics card in PCI Express 2.0 x16 mode and if 2 cards are used in crossfire, they run in the lesser PCI Express 2.0 x8 by PCI Express 2.0 x8 mode.
To run 2 ATI graphics cards in full PCI Express 2.0 x16 by PCI Express 2.0 x16 or 16 by 16 mode you will need the more expensive 790FX chipset based motherboard which can run up to 4 graphics cards (single X16,dual X16, triple X16/X8/X8, or Quad X8).
According to a recent Tom's Hardware review of a Cyberpower (I think?) Phenom II X4 955 based PC in which 2 ATI graphics cards were used in crossfire on a 790X based motherboard in 8 by 8 mode it had noticeable slower benchmarks than a 790FX motherboard.
My opinion though is that when using a budget CPU such as yours it might be best to just use one graphics card and don't bother with crossfiring 2 separate ATI graphics cards as there are substitutions that you can use instead like a graphics card that is already crossfired on one card like the 4850 X2 or 4870 X2 cards.If you change your mind and desire a much less expensive motherboard with just one PCI Express 2.0 x16 graphics slot you can add a cheaper 770 chipset motherboard to the list.In addition there is also a AM3 780G (G means Integrated Graphics) motherboard.

Thank you soooooooooooo much  
I now actually now what X and G and all those random numbers in front mean  

The motherboard I'm going to go with will be M3A780GXH/128M from ASRock.
Link: http://www.asrock.com/mb/overview.asp?Model=M3A780GXH/128M&s=
I'm fairly sure it will support my CPU especially since it says so on the official site but can you double check and tell me if something sucks?
Also why is there a H after the GX, what does the H stand for?

Also it says: Supports ATI™ CrossFire™, Hybrid CrossFireX™ and 3-Way CrossFireX™
Now I have no way what Hybrid is  
I'm guessing 3-Way is the normal CrossFire with 3 Graphics cards?

Don't worry about the price, I can get the motherboard here (Japan) very cheap. For some odd reason though the processors are more expensive here than in the US, that's why I decided to go with an X3 and not an X4.

Sorry for all my questions, it's just that you seem to know everything I want to know  

Hybrid crossfire means that certain low end ATI cards will work also together with the Integrated Graphics in crossfire mode.So the designation H probably refers to this (Hybrid).
One such card is the HD 3450 series.If used it provides decent light gaming ( or good for older PC games).
I'll guess that when run in 3 way crossfire on that motherboard each card only runs in 4 X 4 X 4 mode (or maybe 8 X 8 X 4 mode ) for this motherboard (not sure),Apparently over at newegg it has some good reviews although there are few of them (I am thinking that this might be because it's a fairly newly released motherboard).

By the way thanks for mentioning this motherboard.

Apparently for those in the United States if you missed out on big discount Phenom II X4 955 BE and motherboard combo deals over at newegg (Hey I received mine that same day the 955 was sold out) there is another combo deal on this ASRock M3A780GXH/128M AM3 AMD 780G HDMI ATX AMD Motherboard and the next most powerful AMD CPU the AMD Phenom II X4 945 Deneb 3.0GHz 4 x 512KB L2 Cache 6MB L3 Cache Socket AM3 125W Quad-Core Processor with $65 off for $203.99
http://www.newegg.com/Product/ComboDealDetails.aspx?Ite...