I can almost always justify PC parts...within reason. I needed a new GPU, I could have ran out and bought a gtx690 but there is no reason I need that. The $300 of a 7950 means that I have to use it 300 hours on it before it gets me $1/hr in entertainment... and my PC is a HTPC / Gaming PC, so that means at even 1 hr a night on games or watching a movie (lord knows it is way more than that) I'll feel I have gotten my money's worth in less than a year.
I really enjoy playing games, it is such a nice little escape from the world around. If I didn't play a few hours a week (or day), I would be spending a hell of a lot more money going out and doing things.
Plus any money I spend my wife expects to be able to spend as well, yet when she goes and buys stuff I don't nag her for equivalent.
This is so funny, the day I came home with the 7950, she saw the box and was like "What is that thing?... and how much did it cost" ... As she was grilling me I notice two new rugs and a Nu-wave oven. We both looked at each other and almost in perfect harmony said, "We're even".