Thanks for this interesting thread. I undoubtably have bipolar disorder, since I have had hypomanic and mixed episodes, that fit the description to the dot. However, I have always wondered about having borderline personality disorder. Here are the symptoms PC says BPD's have that I have:

Frantic efforts to avoid real or imagined abandonment
-- I have nightmares of being away from my boyfriend, and constantly worry he will leave me, so much that I wish he would go ahead and ask me to marry him so I know he won't leave me

Identity disturbance, such as a significant and persistent unstable self-image or sense of self
-- I have extremely low self esteem

Impulsivity in at least two areas that are potentially self-damaging (e.g., spending, sex, substance abuse, reckless driving, binge eating)
-- Although this occurs during hypomania, except binge eating, which can happen in any mood I am in

Recurrent suicidal behavior, gestures, or threats, or self-mutilating behavior.
--I've been a cutter for 9 years, and attempted suicide many times, hospitalized 7 times

Emotional instability due to significant reactivity of mood (e.g., intense episodic dysphoria, irritability, or anxiety usually lasting a few hours and only rarely more than a few days)
-- I have mood swings that can sometimes last for just a few hours, which is different than my bipolar episodes

Inappropriate, intense anger or difficulty controlling anger (e.g., frequent displays of temper, constant anger, recurrent physical fights)
-- Especially when I was a teen I had horrible anger issues

Transient, stress-related paranoid thoughts or severe dissociative symptoms.
-- I am dx with dissociative disorder, so definitely have this