Always used the car for weekends away etc. But this year for holiday we did 6 hours on the eurostar to Avignon and it has converted me to train travel.
For instance both sets of parents live a good 3 hours drive away (more on a Friday trying to get out of London). We live a 10 minute bus ride from Kings X to get to my parents then its only 1h 15m on the train No one has to drive, we can more easily entertain the kids, play games etc, go to the loo without having to stop. And with a family railcard it brings the price right down. Wish we'd done it sooner.