cainer,
still not decided yet even though the samsung will prob be my choice.
I currently own 4x2TB F4s, 2x2TB F3s, 1x1.5TB F3? (all 5400 rpm) and 2x1tb f3s (7200 rpm).
I had one 1.5TB fail (just died one day within the 1st year of ownership, thankfully was in raid1 so no data loss)
the firmware rev to apply to the F4 2tB is a real pain though.
as you are most likely aware, Samsung sold their drive division so we'll eventually have to find another vendor at some point in the future but for now I believe they are the best choice.
FYI, stay clear of the 2TB F3s (not even sure if they are still sold), they are noisy and vibrate a lot more than the 2TB F4s.