Hitachi is #1 right now for reliability.. they aren't using cutting edge designs. Old platter (many platter) designs and old firmware (no 512e). These are also a favorite of hardware RAID guys as they support TLER. Can't go wrong with Hitachi.
If Hitachi didn't exist, I'd go for a WD. No TLER command support on consumer drives, and many have 512e (512byte sector in software, 4k in hardware, and performance issues can arise).
Samsung is a neck and neck choice with WD. I personally am not a WD fan, and WD has overall done a good job lately.. given their experience and Samsung's relative lack of, I'd go WD over Sammy for now.
Reliability= Hitachi
Cool n quiet (yet still reliable)= WD
My personal favorites are the 1TB Hitachi (2platters) and the 2TB WD Green (3platters). I use HDDs as externals only and don't recommend they are put into an actual system any longer (that's where SSDs go).
Personally, I'm a Seagate devotee, have been for 20 years. But right now and the past few years they've genuinely been inferior to WD (their hated enemy).
Seagate will be back on everyone's list soon, I'm sure of it.. but avoid for now.