Pro-Comp X-Terrain Radials have an E load rating on some models. They are the an on/off road tire, and hold up very well. On a F-250 4x4, they held up 75k miles. He doesn't tow much, but they still held up a LONG time for a tire. They are also aggressive enough to get through a good bit of mud.
I've seen Brute Force 750s outperform a lot of bikes. And hold up just as good. Snorkel the belt and the air breather, its unstoppable. As for power, I've witnessed one burn out in 2wd on blacktop with a 250 lb man driving it... Can't argue with that in my opinion.
But I own a 04 Honda...
The wider tires up front help with floating in water or "water wheelies" as they are known. Other than that, it's personal preference and what your bike will turn. A Foreman shouldn't have problems turning wide tires, but in mud everything changes. Skinny tires are fine for riding on dry...