I don't know how small my ears are. I have tried to use some IEMs in the past with comfort issues. which eventually lead to me discontinuing their use due to pain in my ears.
Right now however, I think I would mainly be looking at number 4, as I run on avg. about 12 miles a week. When I first started running, I ran with an mp3 player and earbuds, but they never stayed in so I stopped using them rather quickly. As I start doing longer runs, it would be nice to have something to listen to so I don't get bored with just my thoughts.