Stapfam is a great source of advice on trail and trail/road bikes.

There are a lot of bikes to choose from. I would have to disagree that when you try a bike in a shop if it does not feel right at first it won't be right. If you have not been on a bike in ages, it is impossible to know what will work for you, i.e what "feels right". I agree that you should try a lot of bikes, buy one that seems to work for you and ride it for a year. At the end of the year you will know more about what you want. Now for this first bike, I would consider a cyclocross or rigid MTB. These are good utility bikes you will want to keep when you settle in to what you really want. I would go steel on a cyclocross (my preference) or AL on an MTB (due to weight). I would stay away from CF at first until your body adjusts and you know what you want.

Good luck - and we grant you a temporary membership until you have reached an appropriate age to post here.