Hmm... After researching a bit more, it turns out that that .hack//sign box set is just the first DVD in the set, along with a bunch of stuff to go along with it.

I wouldn't mind getting all that junk AND the complete series for $90, but since it's just the first DVD in the set it really means I'll be spending at LEAST $40-50 of the $90 cost for the 'free' special edition junk... and I don't really care that much about the extras. Not enough to go out and effectively buy them separately.