In my opinion, go with at least a 1/2 ton v8 with a 8 foot bed. 4x4 is up to you but if you don't buy it now you can't add $500 to $1000 and get it later.
We run both 1/2 ton and 3/4 ton ford gassers. 95% of the summer we use the 1/2 tons for mowing, mulching and running around (made a 1000 mile trip and got 22mpg at 75-80mph). I plowed 3 years with a 98 f150 reg cab 8' bed and a Meyer 7.5 with wings without a replacing a single part. 04 and above 150s are rated to tow 9,400 to 9,900 lbs and handle it with ease. I got a load of asphalt grindings in my dump trailer and the yahoo loading had his buckets mixed so he gave me way too much, turned out the 7,000 I was suppose to get was actually closer to 14,000lbs. The f150 pulled it fine. Anything over a 1/2 ton is just accessorizing a truck that can do the job just fine. Don't get me wrong, everything about a bigger truck is better for some reason. One huge advantage of having a 3/4 ton or larger, is if you have to rent equipment like a skid-steer, you can haul it yourself.