How to build a wheel I'm in the planning stage of building a new bike. This will be a light road bike for city runs and transport. For racing I have other bikes.
I'd like to build the bike from ground up by assembling everything myself. Not sure wether to go for gears or single speed yet, but that isn't relevant to this question:
What parameters would I need to consider when building a set of wheels?
I will probably go for steel rims to get a classic look. I've already found out how to calculate spoke length, and I'll try to find an old fork to mount the wheel on while building it.
The wheel consists of four parts:

Rim
Spokes
Spoke nipples
Hub

Protips on good parts? I guess specially the hub is important. Are there any real difference to cheap and expensive spokes as long as they are not carbon fibre?

What spoke arrangement should I go for; cross-laced or straight. Pros and cons?
In what order do I assemble the wheel?
What is the best spoke tension (given I can measure the torque)?
What tools do I need?

Any general good advice when building a wheel is appreciated as I'm totally unexperienced doing this.
A lot of questions that is. If anything is unclear, just ask and I'll elaborate on it. Thanks in advance.
The best suggestion I can make is to read "The Art of Wheelbuilding, by Gerd Schraner".

As for materials:

Use aluminum, double walled rims. They are stronger, lighter, and believe it or not easier for a new wheel builder to get true and round than steel rims will be.
In addition, steel rims for a road bike will be difficult to come by in new condition.

Spokes:

There are major differences in the strength and pliability in steel spokes. Even if you ignore spokes from other materials, which you should, look at double butted (usually 2/1.8/2mm) steel spokes from DT Swiss, or if you want really high quality, use the ones from Sapim. Read the Art of Wheelbuilding for more detail on why.

Use a high quality hub, something with a forged hub shell, and good quality bearings. Shimano Ultegra or Dura Ace, if you want good, loose ball bearings. Hope, Phil Wood, or any number of others for good quality sealed bearings.

Use brass spokes nipples.

You will need the following tools:


A good quality truing stand 
A set of good spoke wrenches
A nipple driver (broken link, see Park nipple driver instead)
A quality tensiometer 
Spoke Freeze or similar (broken link, see Pro line Accessories or at wheelbuilder.com).
Method of determining spoke length
The components listed above 
Time and practice.


I hope that helps.