We are in the process of re-fencing all of our paddocks at our new place. When we moved in it was all barbed wire which I despise. The horses have actually never received an injury from it, likely b/c they have a LOT of space to roam. However, I hate it with a passion.
We do not have a ton of money for this, so we opted to do our first paddock with 6" posts and used the post pounder to drive them into the ground. Did not use cement. For the rails, we decided to use rough-cut lumber - it is very thick so it will take a LONG time for it to rot, plus it was cheaper and looks great. My only concern is if the horses will chew on the boards; so far so good. If I find they are then I might run an electric wire across the top.
We are still in the process of doing this and once the ground thaws we will be finishing the rest of the paddock. So our fencing is a mix of straight wire, barbed wire and the lumber.
I wish I had an unlimited supply of $$ for this, but I think once it is finished the posts & rough cut lumber will be safe and look good. Just a matter of the horses not chewing on it, which I could solve easily with some hot wire.