You're going to here a lot of different advice on this subject-- more spokes/ stronger hoops/better hubs/ect.....
Don't loose any sleep over it.
Listen to your LBS guy, because he's going to have to face you if the wheels go bad. His choice of XTR hubs/Mavic A917 rims is pretty good-- I'd tour loaded on them, even at 32 holes.
Order your new wheels and don't look back.