The Neopower 650 is $150 after shipping at Newegg. The 650TX is only $100.
The GA-EP35C-DS3R costs $30 more than the GA-EP35-DS3R and all you get is (pointless) support for DDR3. You can't use DDR2 and DDR3 at the same time, and throwing out DDR2 just to put in DDR3 is a waste even if DDR3 becomes much cheaper in a year or two.
That Seagate is very nice, but $240 for 1 TB is a lot. You can get two WD6400AAKS disks for only $200, and you'd save $40, get 30% more space, and lose no performance whatever.
A warning about the Antec 900 case: It does not include a system speaker - you know, the one that gives the short beep indicating that the POST passed - at least, mine didn't. And my DS3P didn't have one built into the motherboard.