I have a new rear wheel for my commuting & light touring bike. It's a Shimano Dura Ace 36 spoke hub laced to Mavic Open Pro rims. I purchased this from a reputable wheel builder on close-out for $125.
I'm going to have my LBS build a matching 32 or 36 spoke wheel. I can find 105 hubs for as little as $16 while Ultegra cost 3 X as much and Dura Ace are even more.
I've been using 105 hubs on my cyclocross bike without a problem.
Is Ultegra or Dura Ace worth the extra money? The finished wheel will cost $100 to $125, so I don't want to invest in a low end hub on what should be a long term investment.