Couple of comments:
- Drop to E8400 because if you are overclocking you will make up the difference in clock speed to an E8600 and you will save yourself money ($100).
- For overclocking look at a 4GB of DDR2-1066 from Corsair, Geil, OCZ, Mushkin. The quantity is not so important, and 4Gb is the sweet spot, whereas extra speed will help you.
- The money saved on the processor could upgrade one of those 4850's to a 4870. Although you would need another 4870 to crossfire. You might find that one 4870 would cope with the 24".
- PSU, suggest Corsair 750TX. Should be about right for your needs.