I would honestly not op for the rosewill PSU, its more of a home brand to Newegg and TBH doesnt ahve a too good track record. Try something from Corsair or even better PC Power&Cooling
Western Digital has come out with the "Black" series of Caviar drives, look them up; they are very fast adn quite a bit better than Samsungs new F1s.
Change the AC freeze pro for a Thermalright Ultra-120 eXtreme, couple that with either a 1600 (quiet) or 1900 (louder) Scythe S-Flex fan and your golden for a nice O.C.
In term of memory, you should go with either Crucials Ballistix PC2 6400 DDR2 800Mhz 4-4-4-12 2T 2x2Gig Memory kit or Corsairs PC2 8500 DDR2 1066Mhz 5-5-5-15 2T 2x2Gig memory kit, both use the better high density 1024Mbit Powerchip ICs, so they both have basically the same overclocking potential.
Either set can reach approx. 1150Mhz 5-5-5-15 2T with 2.2-2.25volts.
If your looking for a even better high density kit, the Corsair PC2 9136 DDR2 1142Mhz 5-5-5-15 2T adn can reach 1200Mhz using the same latencies with roughtly 2.2-2.25volts.
Theses are the best high density DDR2 modules out there, and to be honest its what you should buy since the 512Mbit Micron D9Gxx based stuff is EOL and now almost impossible to find.
Also, get a P45 mobo, they clock like beauts