As someone who owns and uses a couple different S&S coupled travel bikes, I'm oft asked for opinions and chatter on this topic when people decide riding their bike wherever they travel is right for them too.
If you're talking road bikes, here's my recommendation. Everything is right about Andy Hamsten's bike. First, you can tell a bike has street cred if it has your face, standing on the Giro podium, on a sticker on the seat tube. Most of us can't do that, but we can at least follow design cues.
If you deviate from this, have good reason in your mind why you're doing so. Without needing to justify his library of experience, everything he says is right about a bike to ride and travel with - so click through the pictures and contemplate. Big tires, neutral geometry, solid build, that can go anywhere with you. It's fad free, well crafted, and just right.