If you elect to use hardware raid, you'll need to configure that raid card appropriately. If you elect to use a "JBOD" (just a bunch of disks, where each disk can be accessed on its own) you should probably use something equivalent to raid that will allow you to stripe your work across the disks, as well as provide a level of fault tolerance. Raid on a hardware card is more widely accepted as the "normal" way to do locally attached storage, however many people use ZFS to manage their disks instead of a raid card. This has its own pros and cons, and may not be appropriate for what you're looking to do.
If you choose to use standard raid, you should use the hardware raid card on your server rather than software raid. You will want to ensure that caching is enabled, and that you have a cache battery installed. It's an optional upgrade, so make sure you're getting it.