I like the idea of this but not so sure in practice. Currently I live in a house that has a living room with two giant bookcases filled with books and a porch full of DVDs and CDs accumulated over the years. These days I have books music and film covered digitally but I really don't feel I could bring myself to part with the physical media I have collected and spent large amounts of money on over the years. That said I would feel better with the extra space and I couldn't tell you the last time I actually watched a DVD or took a book out of the shelves. How did people square that circle? Did you all just write off the money spent acquiring things?
What I did was made a spreadsheet of all my music albums, movies and books. Once done, I separated them into piles:
Start with Movies:
Pile A: Stuff on Netflix, iTunes etc. - This stuff you don't need, this is available to you for a cheap $ per month. Sell this stuff, or if you can't sell it, donate it.
Pile B: Collectors stuff or stuff that isn't online. If you do want to keep them, show them off in style, or sell them to a collector if you feel that they don't work for you anymore.
Pile C: The stuff that means something to you. Like for me, I have a book that my mum gave me. Have read it so many times but gives me so much value I am keeping it.
The thing you have there is; you are holding onto the idea of you have spent so much money on "stuff." and you are keeping it because of that. What you should be asking yourself is: Does it still bring meaning and joy? Remember, forget the money part. You have already spent the money so the money is gone, only the item remains.
The hardest part is moving past the idea of keeping it. Once you have sold, donated, binned etc. the first one, it will change and be easier. Trust me. I collected a lot of Star Trek stuff over the years that gathered dust after I got it. Once it was gone, my memory of it is still there and the money I got from it helped me take my wife down the aisle. stuff < marriage in my case.
You have already taken the first step by saying "I would feel better with the extra space." Think about it.
I feel like I am preaching... Sorry!