wow im going to have some fun with a 2500 budget. for your best graphics cards for tripple monitors i would say either sli gtx 770 4gbs or 7970 ghz xfire. the 7970 has more cores and a higher memory bandwith but only 3gb of vram but it should be more than enough.
both come to about $900 plus or minus
either i7 4770k for 350
or fx8350 for $180
h100 or equivalent about $120 or custom loop ~$250