Driving can still be cheaper than flying if you have 2 or more people traveling together. It would be tough to beat trains and buses, though.
In the case of trains, it depends very much on where you are and where you're going. For example flying between basically any two European capital cities is almost always cheaper than taking the train.
Traveling with a family on a fairly short / medium-haul trip (no overnight stay necessary) with lots of baggage? Driving will trump airfare costs for certain.