Looking for the right breed for me.?

I'm looking for the right breed of dog for me. I want one for walking as I walk about 6 & a half kms a day and plan on taking the dog to the rec reserve on weekends for play a few times a week. however I don't have a massive yard but can fence off approx 20 m by 5 m for a dog suitable for me. also I live in a rural area. I was thinking of an australian cattle dog (red or blue heeler) as i've had two in the past and were amazing animals! but was wondering if there would be another suitable dog also I work 35 hrs a week. any suggestions?? want low maintenance in grooming too.