Agree with Dan on the Aygo, my missus picked up a 3 year old one earlier this year with 8500 miles on the clock. Shes a community nurse so needed a car with very low running costs and it seems to be working out great, I actually enjoy driving it around the city. Maybe not great if you have lot of motorway runs to do but then its not really designed for that.
Watch out for water leaks and raspy exhausts, they come with 5 year warranty's though so shouldn't be a problem, I also think the new ones look good