From next April the administrative county of Cheshire (UK) will be split in two. With the mapping I did yesterday in Winsford, one of the halves, Cheshire West and Chester, now has all its public roads mapped and named. Of course there will still be some omissions and mistakes but the systematic approach should keep these fairly few. There is still scope for more mapping detail, especially on areas done two years ago, but applications like Nestoria (http://openstreetmap.nestoria.co.uk/) could cover the area with confidence.
The area is mixed urban and rural with a population of 328,000 and an area of 917 km2. (This is about the same density as England as a whole. I'll try to get round to doing the statistics as described in http://wiki.openstreetmap.org/index.php/Completeness_Metrics)
Cheshire East is not quite so complete but is progressing fast, and there is plenty to do in neighbouring North Wales, Wirral and Runcorn.