Carbon or Titanium - What would you do?

Currently have steel for the weekend and longer rides and a selection of aluminium for commuting / short rides.
Thinking of building up a new bike (fixed) for best.
I could go for an 'off the shelf' Dolan Seta or go for custom Ti for three times the price.
What would you do?

Obviously the thrice more expensive option...

Jokes aside if you want to build something special then make it special. Also bike for life, fitted vs. standard geometry etc.

Come to think of it I'd go for a stainless steel custom build instead.

What do you mean by "best"? The bike you ride to church?

I hear ya. Annoyingly the Seta geometry is absolutely perfect for me; hardly any different at all from my steel. If I got a Ti frame it would be pretty much the exact same geo as the seta just with the advantage of a pair of bottle bosses...

I'd buy a 70mph electric mountain bike and ride it towards Dover on the M2.

In carbon or ti?

Li-Ion, obviously.

Custom Ti from Waltly in China...

Certainly not thrice the price, I'm loving mine so far. They'll build whatever you want

Get one of these...

Well I've finally pulled the trigger on some custom titanium. I don't plan on it looking anything like the monstrosity above though!
May post a timeline in current projects if I remember to take photos.