A thread over at http://ask.metafilter.com/251359/I-think-i-might-be-cursed discusses what to do after too many drive failures. There are quite a few good posts which lead to the conclusion that Synology is the way to go.
The discussion also deals with Raid 1 versus Raid 5. In fact, reading that thread led me to do the analysis in my recent post "Raid 1 vs Raid 5 Cost Comparison." This post was what got me thinking:
Three WD Reds ($300): two for a RAID1 setup, one for external off-site backup.
Synology NAS, HP Proliant microserver NAS, etc. ($250 - $400), or something similar.
Garden-variety small UPS with a USB status port ($50).
Gigabit ethernet switch ($30).
RAID5 for most home folks isn't a good investment when compared to RAID1 unless you're enclosure-limited, etc. As you've noted, there's no added redundancy, just better storage utilization; compare the cost of three N-sized drives to two N*1.5-sized drives. (3 x 2TB == $330, 2 x 3TB == $270) Factor in the off-site drive's usability as a hardware-identical hot swap (once you replace it with a drive from your local computer store, of course) and RAID1 only looks better.