Hi Salil, your latest build looks very nice.
Since you're using a 46" TV, I agree that 4870x2 would be the better choice because you save money not only on PSU but also on the motherboard. Also, having 2 GTX 280 would generate a lot of heat and consume a lot of power (a single GTX 280 is already a power hungry card let alone 2). I however do not recommend Sapphire because their customer support is not very good. Go with the HIS HD 4870x2, it may cost more than the Sapphire but their customer support and warranty are far better than Sapphire.
I also suggest the Samsung 22X DVD-drive, it is only $1 more than the Lite-on (that one is $23.99 now) and Samsung makes quality DVD-drive.
How about the OS, do you already have one? Also you mentioned you're overclocking, I suggest you purchase a much better heatsink and fan for the CPU, something like the Xigmatek HDT-S1283 and pair it with the Retention Bracket for easy installation.
Hope that helps.