My family used 6 wire high tension electric wire. We did have a horse crash into it once because she didn't see it, but she bounced off.
The only problems we had with it: one time while dividing the pasture, my dad had only two stands up, the horse didn't see it, and she did run through it and break it. It did cut her chest, but thank goodness she was alright. Another time the fence tension had dropped so the wire started to sag, so the horse decided to jump it. So make sure the tension stays up and it's at least 5 feet high!
It wasn't very attractive, and over time we replaced it with three board fence. We had vinyl three board in some spots, and it looked nice and was easy to put up.
I would strongly recommend just paying someone to come put up a fence for you. I don't consider wire a long term option. Fencing is expensive, but a good fence is worth it.
Never ever ever use barbed wire. A former family friend who was a terrible horse owner (for many many reasons) put her mare in a field with barbed wire and she got caught up in it, and had to be put down. It was very sad. But something similar could happen with electric wire, which is why I say it's not a good long term option.
A good option could be the wooden posts with a top rail, but then wire stands underneath it. I don't have personal experience with it, but if I was planning out my farm and wanted to save, I think I could use that.
A good book that might help you plan is "Horsekeeping on Small Acreage" by Cherry Hill. It goes into things you may not have thought about before, like what will you do with all the manure, field placement, drainage, etc. I high recommend it!