My plan, as others have suggested, was loading the OS and major software programs onto a small SSD. Then, I planned on utilizing a RAID 0 on a standard HDD for storage, and having a separate RAID 1 HDD to back up the two RAID 0 HDDs. If there is no real benefit in system performance from the RAID 0 setup, I will gladly forgo the added complexity of the RAID 0+1 arrangement. Instead, I'd probably just opt for a RAID 1 setup, and back that up onto another external HDD so I'd have triple redundancy of my images.
Ok, so, you seem to have a mis-understanding of what RAID 0+1 (or 1+0, aka RAID10) is. It's doing a strip (RAID0) across mirrors (RAID1), or mirrors across strips. As opposed to having a separate RAID0 then a separate RAID1.
Plus, RAID is not a backup, regardless of if it's 1, 5, 6, 10, 50, etc. It's a means to higher availability and sometimes better performance.
If you're after performance, invest in a decent SSD. Otherwise, if you want storage space/reliability, go for RAID1 or RAID6 (RAID5 is relatively fragile). 0+1/1+0 is best if you want a better balance between performance & reliability.
I agree, backup to an external source (and then to another geographically distributed place) is the correct idea.
If I were you, I'd invest in a better CPU, and then do a RAID1/6 on your storage drive if you want enhanced reliability with a proper backup strategy. And either invest a significant amount of money into a proper RAID controller...or go for Windows software RAID. It'll be much more reliable and theoretically portable as opposed to whatever motherboard half-assed software RAID that they do.