Ordnance Survey recently released beta versions of new open datasets - Open Map, Open Roads, Open Rivers and Open Names. Along with the data there are some associated stylesheets to let you recreate to classy OS styles in your favourite desktop GIS.
Using the OS stylesheets as a starting point I decided to roll my own for use in QGIS. First up was a Toner-like set inspired by the Stamen team's classic style. The black and white background is great for overlaying your datasets using nice bright colours for emphasis.
The second set of stylesheets was started using Cloudmade's Midnight Commander OpenStreetMap tiles as a base.
I'm not sure when I will ever use this but I just like looking at the map - easy on the eyes. To get the stylesheets visit my GitHub repo.
Map images of OS Open Map Local contain OS data © Crown copyright 2015