Echo what Ben says about going with how you feel. I've only started running seriously in the past few months and Manchester will be my first marathon so really looking forward to it. Up to 10 milers now and need to pick it up.
I'm definitley in the 'running in snow' is fun camp having done a 5 miler on Tuesday in snow/ice but each to their own I say and if you're not confident or don't want to run the risk, then stick to the treadmill. This may have something to do with me being a novice so I'm sure I'll learn as the running years go by
Think I'm going to be sensible and do the Leeds half marathon in May to give me a taste of longer distances and continue with my training throughout 2013. Hopefully work my way up to a marathon in Autumn 2013 or even 2014.
Thanks again all. Looks like a great community here