RAID 10, 3 drives or 2 drives?

RAID 10, 3 drives or 2 drives?

Drives are very cheap these days. Would it be worth it to increase the
group size from 2 to 3. I found 1TB drives for $60. I feel as if the array
is very vulnerable to failure in a 2 group setup since drive failures are
tightly correlated and it would be worth adding another drive to each RAID
10 group for the added redundancy (all 3 drives per group have to fail).
Am I better off going this route, or sticking to a 2 drive per group
setup. What would be considered "best practice".
Basically:
1TB
1TB
1TB
1TB
1TB
1TB
-vs-
1TB
1TB
1TB
1TB
1TB
1TB
I like RAID 10 setups due to their simplicity.