i'll agree that king headsets are more worth the money on mountain bikes, or even BMX bikes (although there ARE better/stronger cups available). but on a road or fixed gear bike, i just don't see the point. the amount of abuse that a headset sees from these bikes, vs. MTB/BMX is really not enough in my opnion to warrant a $100 headset with a 10 year guarantee. if you get a $20 headset and you take care of it (install and adjust it properly and overhaul it once a year), it'll last for years and years. i really think my 105 headset failure was a fluke, but if it was loose-ball i could've done something about the problem sooner, like lubed it more often or actually cleaned it. my issue with the 105 HS is that the bearings aren't sealed at all, they're just encased in a cartridge, which you can't get inside to check and see if it's rusting out or being damaged. when i pulled the cartridges out, i could barely move them with my fingers. this, compared to my loose-ball headset that's seen way more harsh weather (probably 5 or 6 years before i bought it 3 years ago). and is still going strong...and i've only overhauled it once. it'll probably continue to work fine for another 3 years, maybe even beyond. when it dies, it dies, and i'll get a replacement (if they're still making 1" threaded headsets in 3-4 years).
for me, $100 would be better spent spread out over a number of different little parts that are actually disposable, like chains, tires, or brake paraphenalia, or go into a fund for better wheels or something like that. that's just me though...