[coyote1982]

Thanks everybody for your suggestions. I looked some more at the store's website and found these things:
instead of buying the OCZ DDR2 Reaper 4096MB (2GBx2) DUAL CHANNEL 800MHZ CL4 (OCZ2RPR800C44GK),
they also have the OCZ DDR2 ReaperX 4096MB (2GBx2) DUAL CHANNEL 1000MHZ CL5 (OCZ2RPX10004GK) but it's 17% more expensive. I'm not sure it's worth the extra cash.
They have the G.SKILL DDR2 4096MB (2GBx2) DUAL CHANNEL 1000MHZ CL5 (F2-8000CL5D-4GBPQ)
and the G.SKILL DDR2 4096MB (2GBx2) DUAL CHANNEL 800MHZ CL4 (F2-6400CL4D-4GBPK) as well (both are cheaper than both the OCZ kits).
I'm a little confused - what has the bigger importance: frequency or CL & timings?

Also, I was planning on putting all this system inside a HEC Compucase 6AR6 or 6A19 case.
I'm guessing you guys are gonna tell me to spend more money on a Thermaltake case but is it really worth all the money? I'm trying to keep the budget from going too far...
I'm also still not sure why would I need a better/stronger PSU. How strong should it be? 450W? 500? 550? more?
I still didn't read that forum post about cases but I will when I have more time tomorrow.