I'm a big fan of cars with high mileages. People are generally scared of them so they are cheap. If you get one that has done lots of motorway miles with full service history then they are generally good for ages. On the other hand an older car with less miles with loads of owners and patchy service history can be much more trouble.
I bought my 20V with 111,000 miles on the clock and it had no hidden faults and has just given me a fairly trouble free year of motoring. Our other car is an ex-fleet Volvo 940 that had 94,000 miles at 3 years old. We still have it 12 years later.......
At the end of the day, mileage is just one of the things to take into account when buying a car. If everything else is good then I wouldn't worry too much.