Weight is also a consideration, if you're the type that is interested in that target. (I am, for one).

You can set the bearings with a regular compression plug, remove it and replace is with Tune "Gum Gum" and a custom top-cap of your choosing.

Tune "Gum Gum" is really good - and light. It won't damage the carbon steering tube and it's removable.
Extralight also makes a good rendition of their own, but it's damn pricey. It's the aforementioned "Ultrastar"

See the weightweenies forum for recommendations via a search.
Also, see what the options are at fairwheelbikes.com - that would give you a good measurement of the options available to you for light-weight parts.