As others have said go to a proper running shop where they will analyise your gait and get you the right shoe for support/cushioning and take into account over/under pronating. Forget what they look like, they are there to do a job. Most likely you will end up with Asics, Brooks, Sauconay, Mizuno or New Balance, that said the main"fashion" brands do of course do more serious running shoes.

For me personally I won't wear anything except Asics Gel Nimbus, and am on my 5th pair. They aren't cheap around £100 but are well worth the investment.