Bob Marley
To remind me that all this exercise can't be good for you. Go and chilli out in a nice comfy chair with a drink and relax. (says the man who is nervously waiting on his London marathon application to come back in October... )
Seriously? Iron Maiden - "loneliness of the long distance runner" or any mid 90's techno or goa trance, I get kind of zoned out when running anyway...