I think many visitors to London the most they see of the city's canals is the customary visit to Camden. However there is a real community of people living in canal boats, and it's quite enchanting to wander around the area nicknamed Little Venice, near Paddington, north London.
In fact, it's a great walk along Regent's Canal, from Little Venice, through Regent's Park, and on through to Camden. From Camden you can also continue on to uber trendy Angel. If you were to walk all of that end to end, it's a pretty decent walk, so you'll need some nice weather! But even a little walk along the canal is a nice escape from the busyness of the city. Along the route, there will be occasions where you have to leave the canal-side to walk on the street.
From my work in Regent's Park, I would go for a morning jog along the towpath, and watching everything change so dramatically with the seasons was stunning.