Hi Dave,
I'm using a Perma Cool fan, from Summit Racing. A little less expensive than the big name fans, like Flex-a-lite and they have dozens to chose from, depending upon size, thickness, diameter and CFM required.
You get better cooling, control over the cooling and the ability to turn it off when fording water.
An electric is quieter, doesn't use as much horsepower to turn (that alone is the best reason) and there usually is plenty of room after you remove the stock fan from the pulley.
Most electric fans come with their own shroud, built into the fan support bracket. There are universal mounting kits that make installation simple, check out the Summit web site.

Summit Electric Fan Page