I will also endorse the Bike Friday/Brompton suggestion. I ride a Bike Friday, actually sold off all my other bikes once I had it a while, because I never ever rode them. The 20" wheels are bombproof, incredibly nimble yet stable in city traffic, super easy to dismount/remount at busy intersections, and the Bike Friday rides and fits like a fine touring bike (built to size). If you know what size is right, you can also find some very good deals on used ones in great condition (I did) to save some money and then tweak it as you will. Bike Friday also sells "pre-loved" bikes that they fully recondition and warranty.
I couldn't get comfortable on a Brompton but many people love them and the fold is absolutely fantastic. There are plenty of shops where you can go try one. To try a Bike Friday, it's best to call them and they will put you in touch with a local shop or owner.