System configuration is below:
AMD Sempron 140 (Unlocked to dual core)
2x1GB DDR2 800
What I need now is a hard drive, any suggestion for 500GB capacity?
1.500 GB Hitachi 0A37045 CinemaStar 24x7 P7K500, SATA 3Gb/s, 7200rpm, 8MB Cache
2.500 GB Hitachi HDP725050GLA360 Deskstar P7K500, SATA 3Gb/s, 7200 rpm, 16MB Cache
3.500 GB Samsung HD502HI EcoGreen F2, SATA 3Gb/s, 5400rpm, 16MB Cache, 8.9 ms, NCQ
4. 500GB Samsung HD502HJ Spinpoint F3, SATA 3Gb/s, 7200rpm, 16MB Cache, 8.9 ms, NCQ
5. 500 GB Western Digital WD5000AAKS Caviar Blue, SATA 3Gb/s, 7200rpm, 16MB Cache, 8.9 ms
6. 500 GB Western Digital WD5000AADS Caviar Green, SATA 3Gb/s, IntelliPower, 32MB Cache, NCQ
My father mainly use the PC for TVwatching, Newsgroup, etc.
All your options look good, though for his convenience go for a 7200rpm drive, so he can access content faster. And based on personal experience with the brand, I'd pick the Caviar Blue, or the Caviar Green if you want to limit power consumption.