hard drive setup question

[videodrone83]

ok heres my little deal, I am updating my server, right now its an amd xp 2000, running western digi 8mb cache 120gb drives(SE), i have 5 of them running in raid 0, I am wanting to upgrade to 1-2TB of space, but i want to know is it really worth upgrading the motherboard and processor AND ram for SATA? or is it worth getting new mobo/proc/ram for the nice maxtor 16mb cache SATA II drive's, another big question is power usage, what would be adequate power supply for 8-12 hard drives, nothing too serious, i cant see paying over 140-150 for a power supply.