Short answer:
Avoid Seagate. WD and Toshiba are the other options in this not-very-competitive market. If I had to buy based on brand alone, I'd go with Toshiba--they can't possibly be any worse than Seagate, and might even be better than WD.
Long answer:
There have been two big studies of consumer HDDs used in data centers (Google and CMU) and neither one would name names. However, Backblaze did name names in a blog post and they said they had good experiences (and no failures yet) of Hitach 5k3000 HDDs whereas Seagate and WD--even WD RE HDDs--would fail or drop in and out of arrays more often.
Unfortunately Hitachi doesn't make HDDs anymore; they sold their HDD stuff to WD, except 3.5" production (due to anti-trust regulation), which they sold to Hitachi.
Since Samsung sold out to Seagate, there are only three major consumer 3.5" HDD makers now: WD, Seagate, and Toshiba.
Toshiba may or may not dilute the quality of product from Hitachi's standards--it's too early to really know. In any case their consumer 3.5" HDDs appear to have 2-3 year warranties. If Backblaze was onto something, and Toshiba keeps quality at Hitachi levels or better, I would say Toshiba is the brand to get, but without more information it's hard to say for sure.
Seagate by dropping its warranties to 1 year on most consumer internal HDDs is probably signalling something, because presumably if they had more confidence that their warranty liability wouldn't seriously increase by going from 1 year to 2 years, they'd have at least a 2 year warranty. Seagate's handling of problems like the infamous 7200.11 series also speaks volumes as to how they value (or don't value) customers.
WD has also dropped warranty durations for most HDDs, to 2 years, rather than 1 year. Some of the upper level ones like Red/Black/VelociRaptor/RE HDDs get 3 or more years. I suspect WD's HDDs aren't much more reliable than Seagates, but the extra warranty is valuable. I've personally had HDD failures from Seagate, Samsung, and WD all get repaired under warranty, saving me hundreds of dollars, and until recently I didn't even have that many HDDs!