If money is not an issue go with Intel. Reasons are
1. Better CPU perfromance, no way to argue it. Intel is better, and this is coming from an AMD guy.
2. Intel supports MUCH faster RAM. I think it is up to 2500 now, where AMD is 1333, but can suport an OC to 1800.
From there on I AMD supports most of what Intel does, although I am not an Intel guy so take that with a grain of salt. IF I had the money, I would go intel and get a fast intel quad, then load up on the fast ram and a nice VC. Oh, and I believe you can mix AMD and Nvida cards on intel boards. I think your choices of cards to mix, familys of cards are very wide on Intel, AMD is picky.
As fa as which board, Asus has bery highly rated x58 boards and so does gigabyte. It would be good for you to use this site, as well as www.tweaktown.com and www.hardwarecanucks.com to read reviews. Just be syre the MB and CPU you buy are compatible. Socket type is the key there. www.newegg.com is my favorite site for looking at hardware. They have great selection and the prices are very good/ Also reviews there are good, and they list the important specs for you.
Yo run 3 monitors your going to want an AMD 5800 series, or Nvidia gtx400 series cards. Not cheap. Also do not skimp on a power supply. Alot has changed in the last few years. 850Watt is min for sli or xfire. 1000Watt are becoming very common choices. And get a good case, I like the Cooler Master HAF922 or HAF932, but the CM Storm sniper is nice too. Not the storm scout, the storm sniper. There are a thousand cases on newegg, literally.
If you look at the best CPU for the money on this website Intel doesnt even become a recommendation until higher tiers of cost. Unless you are doing some heavy number crunching, I suggest sticking to AMD. There is such a thing as "good enough" meaning, frames per second and resolution (not screen size) for which your brain cant even tell the difference with any increase. An AMD cpu will more than meet this requirement if you pair it with a good video card. You may as well save the money.
Sounds like a good plan. I would suggest buying the best psu you can afford. I like corsair, and antec. Everyone has a favorite. The psu will be the backbone and if you dont spend it now you might have t later to be able to upgrade. 850 watts is a good place to be.
Someone mentioned a CM HAF 932 case. That is a great suggestion. CM also makes a 922, which is a bit smaller but still offers more room than most mid towers. I also like the CM Storm Sniper. It is very close to the 922 in size, but unlike the HAF series is painted all black inside and comes with blue led fans. Big fans, 200mm or maybe 220mm.
As far as ram goes, its really a personal chioce. Keep in mind that you must buy the correct type, ddr2 or ddr3, whichever your MB supports. I run ddr3 1333, and like A-Data or Crucial. You can check the speed your MB supports on the mfg website if it isnt listed on the site you order from. I think the crosshair is ddr3 and probably has a max of 1800mhz with an OC. But double check that.
CPU Coolers are very important if your going to oc your chip. I currently have a CM hyper 212 plus and am happt with it. BUT, I am running only a 720 x3. I think you might need to invest a little more than the 20.00 I spent and step up to a better cooler. www.frozencpu.com sells a million coolers and www.frostytech has a million reviews.
Good Luck - Have fun