I used to think (and it still creeps in from time to time) that you should train at the pace you want to race. I used to think that hill = strength (only) and strides/track time = speed.
I have since learned that speed comes from a great base as well as good strength. Reading articles like the ones linked to above have led me to better racing – I have not completely follwed through yet but the closer I get to doing so the better I race.
I am slowly changing my approach that running is what I love to do and that races are a part of it and not the goal of it.