Pretty obvious poll, do you use 1st or 3rd person view when you are lancing from horseback. I normally always use 1st person when going for the kill, that's not to say I don't zoom out to 3rd person quite a bit still, but when I'm actually thrusting I'm always in 1st person otherwise it's hard to see the tip of the lance (especially if you're on the left side of horse).
Don't get me started about round shields from horse and how it's basically impossible to see your lance when it's on the left side of your horse (in first person). In 3rd person it doesn't matter what shield you use, if the lance is on the left side of the horse, a lot of the time your body blocks the view of the lance.
Only other time I'm 1st person is when using archery or crossbows (and from horse I usually use 3rd person with them). Also if I use a 1h or 2h from horse I'm always in 3rd person. Only with lances am I in 1st person.