Now look when you gone did. Now you're going to have to lower it.
You could run the popular 295/40s and 245/40s, like what N2Trux runs on his short bed. Or, you could step up the sidewall height by running a larger series wheel, like 45 or possibly 50s, especially since you have a long bed. I guess it depends on the look you're going for... staggered, low profile, etc.