I and many others run this setup and make a serious living. If you aren't using version control, hourly backups, nightly clones then you should be worried about your data.
What you describe for backups is a good way to go (I'm still amazed at the number of users with critical data that don't have anywhere near a decent backup system), but it's not the only consideration.
That's all we're trying to point out. Availability (uptime), redundancy, and performance can all be improved from other RAID levels, and a better fit for the user's specific needs.
A stripe set may work for you, but it may not be the best solution for someone else (every configuration has a different balance of the above considerations), and is further complicated by budget constraints (usually what's really needed can't be had, as there's insufficient funds).
From my observations, this is a serious problem with independent pros, and is getting to be more of a problem with corporate situations as well (holding off on tech purchases/trying to piecemeal it together).
The optimal situation isn't in everyone's reach/price point, so while it would be better, for example in my set-up, for our server to be using RAID1+0 instead of RAID5, the loss of a terrabyte of space isn't worth the added security (our most necessary files are kept on a triple RAID1, however).
I agree. As you mention budget, if you had a much larger capacity requirement, 10 is even harder to justify (budget constraints).
For example, lets say the
usable capacity requirement is 12TB (using 2TB enterprise disks). Redundancy = 2 members (to get a fair comparison).
RAID 10:
In a 10 configuration, you'd still need a separate controller of some kind, and can get away with a non RAID HBA (say the ATTO H608). 4x disks on the internal HDD bays, 8x on the card, and place the disks in an external enclosure.
12x disks (WD RE4) $3480
ATTO H608 $400
Enclosure (TR8X) $400
HDD Adapter Kit $129
Total = $4409
RAID 6:
8x disks (WD RE4) $2320
ARC-1880i $600
Enclosure (TR4X) $230
Internal to External Cable $60
HDD Adapter Kit $129
Total = $3339
$1070 difference, for the same usable capacity and redundancy. Sustained throughputs would be around the same as well. 10 would would have a performance advantage for database usage.
For video/graphics work as what's described most commonly in MR (and in this thread), sustained transfers = usage pattern.
I can't say about you, but more than $1k will usually get someone's attention.

So the cheaper solution would definitely be more attractive for most.
Running my desktop in a RAID0 has never frightened me in the least because I am able to get back up and running from a total system loss in a matter of about an hour, and all my files, other than the modifications from the most recent save, are secure. For me, the trade off of time saved by using my configuration are worth the possible time lost.
You've put together a nice setup from what I can tell (1 hr recovery time = nice for a DAS implementation).