any i5,with mobo tat support cf/sli.any corsair or ocz ram
important must lowest price!budget problem
OCZ Platinum DDR 3 10666 or GSkill 10666
Gigabyte P55 UD3R
Totally forget xfire/SLI on a p55 set up just get yourself a decent card like a ASUS 4890 or if you can afford get a 5850, if you seriously want xfire on P55 save up for a Gigabyte UD7 so that you get the full 16x + 16x , it has an extra gfx chip onboard giving you full xfire but it wont be cheap
Samsung 1TB F3 very low price atm
With i5 you need to get yourself a good cooler, youll need to check that out yourself because there has been a dismal choice of skt 1156 coolers up until recently so you need to look for yourself, i use a Noctua U12P which is excellent but again it was expensive.