In reply to samuel_w:
For mixed running with a bit of road but mainly tracks, fields and forest paths, I've had several pairs of Mizuno Wave Cabrakans. I like them because they fit me well, are stable and reasonably precise. They have decent cushioning for road, are adequately grippy on wet tarmac, and confidence inspiring when I need the extra grip offered by trail shoes. (If it's really muddy on the same terrain, I'll wear Wave Harriers.)
Road shoe or trail shoe? Depends on the proportion of each that you do; I prefer to compromise my speed and commitment on-road rather than off.