Feel for you buddy, it is a really sad time. At least you know he'll be at the never-ending beach in the sky, with strong legs, bright eyes and a spring in his step, watching down over you all.
We lost our beautiful blue (heeler) friend of 16 years last year. They are always with you though. Our old boy's collar still hangs on a hook near the front door ready for his next walk. I think that collar will always hang there.