Only change I'd make is drop 1 of the Seagates for a Western Digital Raptor SATA drive. Split it into 3 partitions. One for Operating System, one for your swap file, and one for game installs. It is a noticable difference, twice as fast as the Seagates. Keep the second Seagate for storage and big software that doesn't need the performance (office, whatever else).
I'd drop the wireless keyboard & mouse. That's just personal preference though. I hate needing extra batteries, and I refuse to have a mouse weighed down by them... but I'm a twitch gamer at heart.'''
Maybe, depending on the price gap, jump to the 512mb version of that video card.
That's it though, that machine will be really fast as you've got it spec'd