[quote name='jp0213']If you are getting those two, I would definitely recommend getting the Torchwood: Children of Earth blu-ray set as well.[/QUOTE]
Seconded - Children of Earth is an amazing pieces of sci-fi. Very gripping.
As a side note, I have yet to watch any of the new Doctor Who (will be soon, though), but had watched all of Torchwood on it's own and was able to easily get into it (in case someone is worried that as a spinoff, they might not understand it without watching Dr. Who).