I've owned both Fords you're considering (I have a '02 F350 and owned a '05 F150). For a DD and family vehicle, I think the F150 is great. It drives nice, is very quiet, and has plenty of amenities. The engine is powerful, but it just doesnt feel that way...it doesn't have the acceleration or raw V8 feel you would expect. Overall, it handles and rides like a nice SUV with a pickup rear end...very similar comfort to my wife's Expedition. Ours also had backup sensors, which is great for parking.
My F350, on the other hand, rides like a pickup (the phrase "brick *******house" comes to mind). I absolutely love the truck and will never sell it, but it handles like a tank and I feel every crack in the pavement. It has absolutely no body roll in the corners, which is surprising for a 8,000lb rig. Granted, the F250 will ride a little softer, but probably not that much different when empty. The diesel is very powerful, but it's also loud and carrying on a conversation with my wife or the kids in the backseat at highway speeds is challenging. The fuel is also about 50 cents more expensive here than regular unleaded. The cabin on my F350 is pretty barebones as far as luxury goes, even for a Lariat. The SuperDuty line got much more luxurious in 2003 or 2004 with the King Ranch, etc. I have power everything and air conditioning, but that's about it. Ford also switched a fold down rear seat a few years later, which is a very nice feature (mine is still the old tilt forward rear seat like you'd find in a pickup from 1971). Still, you can't beat the power train, IMHO, and I love the diesel sound and feel. It's like driving an old Army deuce-and-a-half truck.
For the uses you describe, I would buy a F150...it's a better value if you're going to be doing only light towing.