On Monday our beloved BlackDog was PTS at the age of 12 and a bit- we are devastated, though given her age it was something we were expecting, despite its very abrupt passage 
While we could never replace her we have always known that we would have another dog, and have had many conversations over the years about our theoretical "next dog." However our lives have changed radically over the last couple of years and the breeds we would normally go for are no longer appropriate for us. We have some vague ideas but what we are really thinking is not only a change of breed but also a change of group- a bit scary for us dyed in the wool dog folk :o
So any advice or recommendations would be greatly appreciated. This is us:
Family: DH, DS(8) and I. Both DH and I are experienced owners.
Other pets: 4 yr old (entire) working cocker dog, cat
House: Small cottage with yard, adjacent to open fields
Working: We both work but have always had dogs that could be left for reasonable periods. Our cocker can realistically be left for 5-6 hours if he has been walked and fed beforehand and I would want a breed that eventually could be left (though I know this will take time) In the interim, I work a 3 minute drive from home so popping back midway is no problem.
Our life: We are outdoor folk so want a dog that can keep up with us and is not going to hide under the bed at the first sign of rain. I have worked several breeds of dog at agility (none of them "traditional" agility types) and this is something I would probably like to continue with.
The dog: Smaller in size (no bigger than a springer really but may manage to persuade DH compromise a little) Not too fussed about clipping or grooming as long as it was not excessive. Cheerful and biddable but with a spark (I am thinking terrier :)) I particularly am used to dominant dogs and quite relish the challenge, certainly more than I would want a lap dog. Most likely a bitch but again we are not 100% set on that. Given our DS and our other pets, I think we are really looking at a pup rather than a rescue.
I should also point out that ideally we would look for this theoretical dog to come home at the beginning of the summer holidays, thereby giving us a decent length of time to work and bond. I am asking this now as I understand there is much research to be done and the wait for a suitable dog can take months.