The jump from $4K to $8K gets you a name, Serrota, and some personal fit. Kerry's a tall guy so he can probably use a custom fit bike.
Personally, if i were buying a steel bike and looking for a custom fit I'd probably just go to a local builder. Most of them do good work for a lot less than $8K. But I'm a notorious cheapskate and don't give much of a hoot about names.
I've been riding Ti lately and it's pretty nice. Went from a Lemond Zurich 831 frame to a Lemond Ti frame with the same geometry. I had a frame failure on the Zurich; it cracked near the downtube water bottle boss. The difference from steel to Ti is small, but I think noticable; the Ti is a bit smoother. I'd probably be riding one of the Trek carbon fiber frames if I could find one that fit me. The Lemonds are nice for me because they've got long top tubes, and I'm long in the torso.
I've never found an Al frame road bike that I've really liked, though. All of them seem harsh. Maybe just the geometry of everything I've tried, but maybe not.