1) instead of i5 2450p, get the 3rd generation i5 3550($209.99 in newegg and amazon)Its modern(ivy bridge), supports pci 3.0 (all gpus now a days are pci 3.0). the i5 2450 cant support 1600MHz RAM whereas 3550 supports it.
2)If you dont want to go high end motherboard get a b75 based motherboard(asrock will be fine) which have 3 6GBPS sata ports, 1600 MHz RAM support etc
3)get a radeon HD 7850 instead of gtx 560. its much cheaper ($179.99 after rebates+$6.98 shipping). It performs much better than the GTX 560 ti source=anadtech. Also the load power consumption is much lower in 7850..
4) regarding PSU, I will recommend you corsiar cx500 which is cheap and reliable.. you can go for the 600v also if u have budget..
5)DVD burner i'll recommend LG.. its the same price in newegg...