I started the first few weeks with Sarah Millican as my trainer and was a great friendly voice of encouragement. When the runs started to get a bit longer I switched to Jo Whiley. For me she was a brilliant motivator. I still use the app now for consolidation runs with Jo in my ear. Brilliant.
I've also found that decent tunes help me on tough days too. I can switch off from my depression and shut out distracting thoughts by running and listening to the music.