Originally Posted by setishock
...my only concern is how to back it up.
If I do a low-cost RAID, I'm probably using a Motherboard's RAID and I can usually use low-end drives (as opposed to WD Blacks, or Seagate Constellations, etc - the so-called 'enterprise' level drives, which contain some extra electronics 'smarts' for monitoring and feedback to onboard systems). Let's say you'd want some ASUS board with three Seagates $189 4th DM0004 drives.
I'd make you buy a 4th one, immediately. But wouldn't let you use it. It'd be in your case, cold, unattached so that if one of those low-end drives failed, you'd have an immediate identical replacement.
Low-End Drives tend to change electronics every few months (or actually, per new assembler house) and, while the RAIDs are usually smart enough to 'accept', they do not operate at Best Performance levels with different electronics and drive-mech's.
If you're paying twice the price for Enterprise Drives, those units usually stay in production (or at least available thru retail channels) for years.
Then, there are questions of expandability. If you get into the 4-5 drive RAIDs, you really DO want a dedicated RAID card because that card's support for problems is so much greater than a Motherboard Maker's "support" (cough cough gag gag).
And once I start using dedicated RAID cards, those often 'need' the advanced electronics of Enterprise type drives. Same as low-end NAS boxes 'need' something in the WD Red Drive range and above.
If you want to have fun with a bunch of dust-collecting parts in the closet, cobble together 3-4 drives as a RAID (have a separate Boot Drive - much easier) and play with that. Mixing capacities (and SATA types) results in a Lowest-Common-Denominator Minus Something RAID, but that's a pretty fun platform to learn with.
(The brand-name INTEL boards have good RAID support, but no other MB maker really supports their RAID levels beyond 'curiosity' levels. If you want the faster RAIDs, go to AMD boards which have SATA-IIIs across the board and use the best of the SATA memory controllers.)