Have a close look at any pro level road bike that still uses an external bearing headset (a reduced number these days) and you'll most likely see a Chris King NoThreadset.
It's pretty much a standard fitment because it is brilliantly designed, impeccably made and smoother than my impossibly well shaved legs. For most riders (including Lance) the standard alloy cupped version is perfect, just choose from a rainbow of colour options, face off the head tube (the biggest cause of premature headset wear) and fit. It'll be the last time you think the words 'head' and 'set' in the same sentence because the sealed cartridge bearings are of a high quality and are well sealed. We know of numerous units that are approaching a decade of daily use. Why, then, spend almost twice as much for the titanium version? Simple, because you want to. Because titanium is, much like the Chris King design, forever. Justin Loretz