I agree with Unsound. You should keep the system for a bit and see if hi-fi audio is something you would get into. If not you will lose little or no money in depreciation 6 motnhs down the road. I don't know how serious you and your girlfriend are but if I had a girlfriend pressuring me to sell something I inheirited, from a loved one, I would simple tell her, NO! The equipment you inheirited is quite nice. Give a try! If you do decide to sell it, you will more than likely have to break it up. Ebay is not the place to sell the equipment you have. Sell it here on the Gon.
Good luck.
Good luck.