I think a capable builder is going to be able to make you a bike that rides like you want from any material...and the modern steels aren't that much heavier than ti anyway. That being said, I do think ti offers some MAJOR advantages - no paint chips, no corrosion. I love ti and would consider it in many ways the ideal bike material. It is more industrial looking and ti bikes all do have that sameness to them (unless painted, which destroys some of the benefits). If aesthetics count, and they often do, I might go steel. Price is a factor as well, though the really fancy steels are no cheaper than ti anyway (and maybe more pricey!).

If you want an EXCELLENT, traditional builder who is also a good bit less expensive than most, I'd strongly recommend Daniele Marnati. Mine rides exactly like what I wanted...it's a perfect expression of my riding and aesthetic preferences. If you want titanium, I'd stick to the larger names - Serotta, Seven, Moots, IF, Spectrum, Black Sheep.