As I start on my first build up, a Serotta Colorado ll, I need to start with the headset. I was wondering which ones I should consider and which to avoid?
Thanks!

Do you need a threaded or non threaded head set?

^+1
And what's your budget?

and what group are you using?

Since it's a serrotta, you should be putting a nice headset on there.

If campy, go with a campy record headset.

If not, I would use something like a Chris King or a Cane Creek classic.

Either route can go threaded or threadless.

It is a threaded headset I will need. I think I like the idea of the Chris King as we have that on our Co-Motion.
Thanks!

Since your life depends on the headset I would use that as the most determining factor then buy a king or a cane creek or a VO

Threadless headset with a quill stem. It might take some work to get it to fit but it will be functionally superior.

Shimano cartridge threaded. Don't know if they are made any more, but Ebay is your friend. Make sure you don't get stuck with one of the leftover useless JIS models that have a 27.0 crown race and 30.0 cups.

The brilliant Shimano design helps mitigate the #1 killer of road headsets: false brinelling. Jobst Brandt has written the definitive exposition on this under the heading: "Indexed Steering".

These headsets are also very forgiving in terms of headtube facing issues, and they install easily.

I've never heard of anyone being killed by a headset. Which of those are the killers?