ASM setup

Hi all,
  I'm setting up my first ASM based database ever. (Just for testing
and learning, NOT for production). I only have 3 physical disks in the
ASM disk group. (4 total physical disks in the server).

  I am loading the OS (Windows 2003 server) on one physical disk as
well as the Oracle installation. I am keeping the other 3 disks raw
for ASM.

  Should I RAID the 3 raw disks (hardware RAID and/or Oracle raid) or
just let Oracle do what it wants with them?

Thanks!