How to choose a disc array for Postgresql?

I am moving our small business application
database application supporting
a 24/7 animal hospital to use 8.0.15 from
7.4.19 (it will not support 8.1, 8.2. or 8.3).

Now, we can choose a new a disc array. SATA
seems cheaper and you can get more discs but
I want to stay with SCSI.  Any good reasons to
choose SATA over SCSI?

I need to consider a vendor for the new disc array (6-
to 8 discs). The local vendor (in the San Francisco Bay Area),
I've not been completely pleased with, so I am considering using
Dell storage connecting to an retail version LSI MegaRAID 320-2X card.

Anyone use any vendors that have been supportive of Postgresql?

Thanks for your help/feedback.

Steve