If you can find it through all its wigglings, the Thames Path is one of the most serene and beautiful walks in London, in my opinion. I’ve done large swathes of it in various goes; I’m fairly sure I’ve done Westminster to Deptford along the South, and Island Gardens to Westminster on the North banks, as well as bits further West in other goes.
On a weekend, when the city’s quiet and the sun is setting, the path can be oddly quiet, except for the sound of water and the occasional dog-walker, creating an almost eerie sanctuary from the city buzz. This appeals to me; it appeals even more, when the light is beautiful, and the landmarks of the centre of town seem to move between the buildings against the sunset as you walk up through the Isle of Dogs.