Let's face it, running is hard enough as it is. I respect each and every person who has what it takes to run on a regular basis. I have tried my hand at it several times with varying levels of success. One thing that has become apparent to me, is that a good playlist makes for a better running experience.
I am also of the opinion that the tempo of song strongly influences the pace of your run. With that being said, take a gander at our "songs to run to" forum. It is broken down by genre for convenience. Feel free to borrow our suggestions as well as leave your mark!
If my opinion is not enough, then perhaps Nike+'s
infatuation with the "powersong" will suffice. Essentially the powersong is a track that comes on towards the end of your run to motivate you to finish.
I tend to create running playlists that start out with a moderate tempo and then gradually increase as my run progresses. I always attempt to finish my run with a "powersong". Try it out, you might be suprised at the results.