Blain,
Thanks for information :)
Mm, sorry, don't understand about prices =(
Cerb,
RAM: Kingston KHX1600C9D3LK2/4GX will be ok?
VGA: I'll use Mac OS X, and, afaik, for OS X there are stable drivers with OpenCL support.
HDD: Thanks for advice, will choose Spinpoint F3.
PSU...