I've gathered a few songs that I find helpful. It helps if the tempo is upbeat, but as you'll see with most of my choices, this isn't the case. It's the lyrics that really help. They speak to the common experiences and doubts that we all share, whether we have Borderline Personality Disorder or not.
Check them out if you'd like, and if you have certain songs that help you out of a funk or create a preferred emotion when you are down, please share what they are in the comments area. I'll put together a list, and your input can help other people.
"The Middle" by Jimmy Eat World
"Hold On" by Wilson Phillips
"Amazing" by Aerosmith
Download "Amazing" MP3
"Everybody Hurts" by R.E.M.