Let me start by saying that I've had the best luck with WD drives, but I've always bought 750GB and below. Plus WD seems to have the best feedback in newegg. I don't buy Seagate because of their poor feedback and it seems that Hitachi is about the same. I don't have experience with Samsung but they seem to get better reviews and feedback.
I now have a need for more storage and looking at what is available on newegg it seems that the WD drives of 1GB or larger have pretty bad feedback. That leaves Samsung along with anything approaching respectable feedback, so I guess I'll have to pick them.
Also wondering if there would be benefits to buying a pair of 1TB drives instead of a single 2TB drive. This is for brute storage, not speed, so reliability is most important. I would not be using any sort of RAID.
I have two Samsung 2 TB drives for SATA 3.0GBps and 2 Seagate 1.5 TB Drives SATA 6.0 GBps. All are reliable, but I'd recommeng the Hitachi 2.0 TB drive based on reviews at Newegg for a 2 TB SATA 6.0 drive.
Reliability is better with a single 2.0 TB drive than two 1.0 TB drives RAIDED, but if you go with 2 1 TB drives you have redundency and backup.
Two drives is twice as likely to fail as one - so if you need 2TB of storage I'd stick with a 2TB Drive.
If this is just for data storage and if performance isn't critical, I'd recommend a green drive. These run cooler, take less power, and don't seem to generate as many complaints. I have a total of five WD green drives in 1TB and 2TB sizes in use for up to two years and I haven't had any issues with them whatsoever.