As already mentioned, it's less likely that you'll need an unstructured shoe. Get to a 'good' running shop. Where are you in this sceptered isle. There are some good ones and some less good ones.
The best shoe is the one that feels best on your foot. Simple as that. One good indicator of a good fit is that you can hardly hear your foot land on the treadmill at the running shop. Noise is wasted energy.
Trail and fell running benefits from having your foot as close to the ground as possible, within the bounds of comfort.
I use the NB MT101 for trails in winter, NB Minimus trail in summer (useless in slop), VivoBarefoot trails for fell / natural trails all year round.
You'll find your ankles and feet get stronger over time using less structured shoes because your feet have to work. A warning though, don't push it too hard too soon. Bones, ligaments, tendons and muscles need time to adapt.
It is fun. Very fun, and very addictive. Before you know it, you'll be night running in the snow over the hills...