1) The GTX 560 Ti 448 looks to be in a sweet spot, price-to-performance I think its your best bet.
2) From what I've read; in real-world performance you won't notice much of a difference between the Spinpoint F3 and Caviar Black, except when it comes to paying for them.
3) Again from what I've read, there shouldn't be much difference as long as its 5ms or less. If you can find a 2ms for the same price why not, but not worth a premium as far as I can tell.
Build looks good, few things I might consider though:
Seasonic makes a great PSU, but something about that one puts me off, might be that its OEM.
I'd consider a Corsair TX750 V2
or OCZ ZT 750W
, 750W will still be plenty for this build, even if you decide to SLi in the future.
Personal preference, but I like the Sony Optiarc
DVD drives, plain face and good brand.
Again personal preference, but I really don't like the inexpensive Antec cases. Good build quality, they just leave out basic amenities like cable routing holes.
I'd check out the Rosewill Challenger
, NZXT M59
, NZXT Source 210
, and Sentey GS-6070