Good move cold.man.....it's never too late to take up the exercise again.
I've got a mountain bike as there are plenty of off road woods local to me but I've also got semi slick tyres which I fit if I fancy a run out on the roads or canal path

If you intend to do heavy mileage the go for the road bike, but personally I like a mix of road and off road
Got to say though, it's playing havoc with my knee joints as I get older