[scheides]

cost aside, the 10k rpm sata drives are as fast or faster than several 10k rpm u320 drives on the market. Now, Eric said he's looking at 15k drives. I've implemented both 10k and 15k drives in various servers at work, and the performance margin is hardly noticable.

For the money, I'd go with 10k sata drives, especially since this is for a workstation-type box. 15k drives tend to be a little on the loud side.

Now, as for mobo's, I still think a dual-proc athlon 64 setup would be a great way to go. In fact, the database back end to our mail system at work is just that, a dual athlon 64 machine with 3Gb of ram , and 4x 15k u320 drives. Of course, that machine cost roughly $6k, but if you want processing power, you're set. The motherboard in that machine is a supermicro, which you may want to check out, Lightning.