I think 31x10.50 is the biggest tire that will fit on a stock 2wd F150. The fronts will rub a little on tight turns, though. I used to have a 95 F150 2wd with 31x10.50 all-terrain tires. I have 255/60/15s on my 92 Flareside, and I like the way they look.
I don't do any off-roading so I run a street tire that is very quiet....size is 255/70-15. My truck has been dropped about 2-3 inches by the PO.....front and back.......My front tires extend about an inch outside the fender well......and do occasionally rub if I go over a heavy dip too fast......mostly some RR tracks around here.... No problems with full turning of the wheels at all.
I guess it just depends on what you need......off-roading or not.