IRO has hubs that are built just like formula's. I build up a wheelset with them and they are nice.
Spokes are pretty generic in price, and vary from heavy to lightweight... DT Champ's are a good starting point. Nipples can be had with the purchase of spokes...usually I go with DT Brass, and if I'm building a thick rim, I'll use 16mm length nipples.
If you are new to everything, It's best to work with your LBS to build up a wheelset, as it can be quite a task for a beginner.