I'd recommend 3TB. For a little more you're getting 33% more space, life and usefulness. Depending on your budget, get the WD Black or a Barracuda.
Depends on what you mean by "a little more", but there is no economy of scale that I have seen in the bigger drive, and I think the 2TB will last me a pretty long time.
As for your suggestions, I had for many years been an exclusive Seagate man, but in recent years I've seen a real falling off in quality and reliability there, and the reduction of the warranty to only 1 year has not helped my uneasy with them. As for the Black, I'm sure it is a fine drive (I have a couple other model Blacks in my system now), but isn't that a little more performance than I really need for just storing and streaming media? I don't even see a 3TB Black on Newegg, do they exist?
Thanks for your response.