Honestly, it all depends on where you use your earphones/headphones and how you use it.
For me, I always hold my source in 1 hand in a pouch, thus I find that the straight plug is the choice for me, especially since the wire doesn't need to bend when I place it in my pocket. Also, a right angled will get in the way of my LOD with my amp, whereas a straight will not.
I've heard issues about stress on the jack, but it really depends on how one carries the source.