"I owned that headphone for about 3-4 years and then I finally purchased an HD600. From that first time I put on my HD600's I was ready to feed the HD595's to the dogs. I was astounded at what the HD600 could do; it was a smoother headphone but offered more detail, more bass impact, and the overall sound quality just felt more hi-fi to me. The initial feeling was like night and day then onto anger / disappointment as I've come to understand that wasted 3-4 years of my life with a lesser headphone."
Poetik, without quoting your whole post but with regard to your conviction about the superiority of the 600 over the 595, you need to remember not only that there's an economic consideration here but that some people just prefer the 595, as amazing as that may seem to your ears. I also owned the 595 for 4 years and was quite happy before I eventually moved on to the 650, and I would still say that despite the organic smoothness and refinement of the 650, the 595 is in some ways a more balanced phone and might well work better on some musical genres. I've always felt the 595 was underrated, at least partly because it's surprisingly neutral for a "budget" phone and doesn't pack the wow factor of rivals like the AT AD700. One thing I'm sure of: if more people listened to purely acoustic music the 595 would be more popular, because that's where it excells.
As for feeding it to your dog, you'll find he's much better off with MeatyBites.