I would advice against JBOD. I did run that once (although Novell, which was the OS on the server I ran it on, called it disk spanning), and you increase the risk of massive data loss a lot, especially if you have many disks. I lost one disk in an 8 disk span, and lost all data from all 8 disks. Sure, occasional bits of data could be recovered, but there were too many holes for it to be useful. Luckily, that was at work, so I had tape backups. Took a couple of days to get a new disk and restore it, though.
Now, I use a Synology DS1324+ NAS, and I really love that little guy. I use their own RAID, which gives me two disks redundancy, and the option to add disks later, even disks of different size and utilize all the size on the new disk (as long as they are larger). So, I now run with 8 disks, 2 of them are "wasted" space for redundancy, and three disks have to fail before I lose a single bit. I intend to get 4 more disks within a couple of weeks, which would give me 40 TB storage, where any 2 disks can fail without data loss. With an external disk cabinet, I can add another 12 disks if I wanted to (although I'll probably just get another 12 bay NAS instead, to reduce single points of failure).
If I wanted even more security, they have the option of adding "hot spares", which are plugged in disks which just sit there and wait until something fails, then are swapped in instead of the failed drive. That way, for it to lose data, three disks will have to fail in a timespan shorter than it takes to rebuild the first.
The thing is, 2 disks out of 12, or even 2 out of 24, is quite a low overhead for that much extra safety. In my opinion, it's very well spent money.