I watch movies from my pc and play music. I quite honestly enjoy a good speaker sysyem more than headphones for this purpose.
However. I'd use headphones for those late nights that my family is sleeping or my wife is studying or in bed and I want to blast my sound to hear that surround sound when play games like COD2 or quake4 and CSS.
If I have family around the house during the day time, I want to hear if anything goes wrong or if anyone wants me or the phone rings etc etc. So headphones at that time, noise canceling in general, would not be ideal. if my family wants to enjoy a good movie with surround sound, I can use the surround sound system.
I would just like some good input from the TH community on which I should buy.
And I am investing in headphones now, and saving for a good 5.1 for like 2 months down the line.
So, to answer your question, no. It is not redundant. It is just more practical for me.
Headphones; the Sennheiser HD590s can be had for around $120-130 online.
As for 5.1 surround setups, the Klipsch 5.1 Ultra ($300) or Creative Progamer S700 ($330~). Below $300 you get tweeterless one-way designs and you can basically pick your poison, none of them are going to be very impressive compared to headphones.