I highly recommend this product for horse fence
http://www.gallagherusa.com/electric-fencing/permanent.component.aspx?mktprodid=786
Starting at about picture 13 in this album is the newest fence I installed with this product. http://s111.photobucket.com/albums/n143/RamboC4/Fence/
You get the low maintenance of high tensile, but the large diameter with the coating gives you safety for horses. Uncoated HT will go through them like a cheese slicer, plus they can't see it. I do NOT recommend Gallagher's EquiBraid. The equibraid we installed less then five years ago is getting shorts. If you really want a braid, ElectroBraid (a competing product) is much better.