Haasman,
If permanently no horses (or other 1000lb++ critters) then go for what you like the looks of. As an FYI, white will show dusk/dirt/etc quicker so a portable pressure washer or similar will eventually be in the equation. So if you have a gravel drive, live in a dusty area, etc it may be something to consider.

Sounds like you are not having animals immediately but likely at some time in the future. So if you go cosmetic only now you may have a real problem on your hands later. IMO, better to put money towards a better product to begin with than have to waste what you did the first go round and re-do it all later.

As for strength...a horse can easily throw a 5'10"/140 lb rider *through* a 4 board, 2x6 planked, 4x4 post sunk in concrete fence. (just ask my riding instructor girlfriend and her looney thoroughbred) Flying rider splintered boards, rocked support posts loose on either side of the breech. That was just the rider...so up the physics to include 1200+/- lbs of horse.

If they want to and more importantly *know* they can, horses are going through (or over if they know how to jump). Luckily, most don't know their strength and size. I've known a mare that would just lean on a fence till it "popped" and others that would jump into and out of any pasture they wanted. They were more the exception than the rule but still, 5'+ fence height is your friend here to discourage that. The only place to uber reinforce is around the gate. 6x6 or bigger (think phone pole) with a metal gate are not uncommon. Random areas along the perimeter take FAR less abuse than the gate and the fence on 30 feet or so to each side (depending on pasture config).

As for cribbing...that is a horse behavior (actually habitual/addictive) and they will crib on anything solid (metal, wood, plastic, etc) An electric wire may discourage but you will be suprised how precise and crafty they can be to finding a way around it. I would work on fixing that with the horse rather than with the fence (ie crib collars, training methods, etc...PM me if you need specifics)

An extension of what Leo said earlier, avoid loose nails/sharp edges/etc and if at all possible keep 90 degree or smaller angles out of the pasture. Horses get cornered and BAD stuff happens.

If there are animals out there it is only responsible to walk the fence periodically to keep an eye out for loosening nails, splinters, etc. Better for the critters AND you get to see if anything is going afoul of all your hard work and $$$ before it gets bad. As the wood ages and whatnot you will get some shrinkage/warping/etc. Minor maintenance saves alot here. Don't be suprised to see bits of mane/tail/etc on spots you wouldn't expect as being high traffic...

Hope this helps...Lee