I am pretty anal about Hard Drives and backups. I have 4 HDD in my tower, two of which are mirrors of the two primary drives. Each night, both of those drives are incrementally backed up to an external hard drive -- on Saturdays, this drive is backed up to a primary NAS drive. And then every Sunday, the primary NAS drive is backed up to a secondary NAS drive.
It's easy enough with GoodSync:
http://www.goodsync.com/
With respect to my main tower, I assign my HDD a 1yr active life -- a depreciation lifespan if you will. I swap my drives out every 6 months, and have for about 15 years. The two primary drives become the two mirror drives after 6 months. And two new main drives are added. After 1 year, the secondary drives are put out to pasture, so to speak, and are used in non-essential things like home media servers, archive storage, etc.
Suffice it to say, I have a LOT of hard drives sitting on the shelves after all these years.
regarding brand, I too am a fan of WD Black. However, I have to say I have never once had a Seagate drive fail. Neither has any WD drive failed. Quantum were a personal favourite years ago as well. The drives that did fail over the years were brands like Maxtor, Hitachi, Fujitsu and some others. Having said that, the quality of Seagate, in my opinion, has dropped noticeably in the last 4 or 5 years, and now I am WD Black exclusively at this point in time. It's just worth the money.