Not that I disagree with airpiratebob's overall assessment that a 747 would be better than a C-17 for normal cargo runs, (I think I said as much in my earlier post, but wasn't specific). However, I gotta counter a couple points:
"1) load it up and it can't go across an ocean on one tank."
Not true. Widely disseminated rumor from when the jet was new. There's now an extended range version, which has 33% more fuel capacity. Anyhow (to quote my former Commander-in-Chief) "it depends on what your definition of is is." Or in this case "an ocean." Atlantic Eastbound (towards the war) no problem. Especially from our next C-17 base, McGuire AFB, NJ. Pacific Westbound, no, not likely. But that's the limitation we accepted when we bought it with other capabilities.
"its not very aerodynamic in cruise." True. Mach .76 at about 15K lbs per hour.
(I won't quote the whole #3) Details on the Charleston incident please. NOTAMS don't show the short runway being "cracked," but I'm out of town and have been for a couple months. CHS's 15/33 was closed about 12 years ago, also. I was under the impression this closure is for the same type of periodic mx as then. Don't get me wrong, though, a big fat jet sinking into the tarmac is pretty ugly - seen it. And you're right that most short strips aren't stressed for us, but a one-time flight of specialty cargo into an almost-stressed-enough runway is do-able, especially if there's somewhere you can get to afterwards for fuel once you've downloaded. We can just AR on the outbound, but Boeing will probably have to pull the AR capability from the commercial variant.
Overall, yes, a 747 would be more efficient and cost-effective. But if someone's looking to buy C-17's it's for specialty work (like the Guppy), not for efficiency.