Well... you're probably going to get two pools of answers... one from the V6-crowd and one from the V8-crowd. I think that I've seen the mileage difference somewhere between 4-6mpg. If you're going to be doing consistent, heavy towing get the V8. Aside from that, I think that it comes down to personal preference... V8 or V6, the V6 can run in 2WD while the V8 (at least the vast majority) are AWD only, and I'm sure that you'll hear things like the V8 has a timing belt while the V6 has a chain, the V8 has piston-slap, the V6 has plastic in it, and on and on. The V8 is one silky-smooth engine, but the V6 is pretty nice, too. I live at 6500' elevation (~19% less HP than sea level) and think the V6 is plenty... it must be awesome at sea level and the V8 has to be wicked!
My recommendation, if it means anything, based on what I have, would be to get the V6 unless you need the V8 for towing/hauling or just gotta have 8 cylinders up front.
Good luck and we'll all be waiting for pictures!
~Doozi