At the moment for internal drives, $50/TB seems to be about as good as it gets. You can get it down to $45/TB with some externals. For streaming 1080p video (inc 3D), a "green" 5400rpm drive is plenty fast enough. For external connections, the bottleneck will be the type of connection but USB 2.0 or better, firewire or gigabit ethernet will all work.
As for drive quality, I've had good success with just about all the different manufacturers. Right now I have 2 samsung internals, a seagate internal, a WD external and a seagate external with the oldest being a samsung I bought in 2006. I prefer to order from Amazon as returns are free in case I get something DOA.