Any Shimano or Campy loose-ball hubs are going to be the smoothest. You need Shimano for your cassette, so anything at or above the Tiagra level is going to roll like a dream. Make sure the hub bearings are adjusted properly before riding (they ship overtightened, which will kill a hub prematurely).
For a rim, I'd recommend something like a Velocity Aerohead (EDIT: OC for the rear) for a good weight/aero balance. You can probably go with 28h rear and 24h front if you're not looking for them to last forever. Keep in mind that the lower-end Shimano hubs are available in fewer spoke counts (higher counts only).
For number of spoke crosses, I'd go look in the Mechanics forum and search to read all the theories and reasoning. Nothing wrong with 3x all the way around, and anything else offers very, very little benefit. Still, it's worth learning about.
I'd recommend butted spokes, because they stretch more to reach tension, which will help keep them from going slack when you hit a really big bump -- so it makes a stronger wheel. There is no practical effect on stiffness.
Last edited by waterrockets; 05-02-07 at 09:04 AM.