When we packed ourselves up in February to visit Emily and Tomás in Chile, I had to decide which camera(s) to take. I didn't want anything too big, too complicated, or too expensive, since I knew I'd be carrying it around all day doing touristy things, there would be precious little time to plan and set up shots, and there was always at least the possibility that the camera would be lost or stolen.
I settled on a used Panasonic GM5, which is tiny, at the time was relatively cheap, can mount any and all of my Micro 4/3 lenses, and despite its size, has a viewfinder in addition to the LCD screen. See the photo below for a size comparison with an iPhone 5s, and to see why I will never be famous for my product photography.
The camera is fitted with a Panasonic 12-32mm lens and an Olympus automatic lens cap. The cap supplied with the lens is an itty-bitty thing that I knew I would lose the first time I took it off. This one stays attached and works perfectly. The next photo shows the camera from the top to illustrate its not-too-deep depth in this configuration. It does fit into a jeans pocket if you don't mind a bulge.
This photo also shows the cheap, generic thumb grip I bought on eBay. As you can see, the camera doesn't have any kind of built-in grip, so the thumb grip helps to hold it steady while keeping my big, fat thumb away from the buttons on the back of the camera.
The 12-32mm lens is nicely versatile, but its longest focal length (64mm equivalent) isn't really very long, and at f/3.5-5.6 it's also not very fast. No problem: I also took my trusty Panasonic 20mm f/1.7 for low-light situations and the amazing little Panasonic 35-100mm f/4.0-5.6 telephoto for when I needed more reach. The whole kit--camera body, lenses, charger with adapter for 240v current, extra battery, extra card, and lens cleaning pen--fits into the very small and obviously well-used bag in the photo below. I'm convinced that this kit gives me much better image quality than I'd get with the phone or any of the current "all-in-one" cameras with their smaller sensors. For the most part, I kept the bag in the car and switched lenses as needed whenever we arrived at the next picture-taking destination.
The bag is a Tamrac 5696 that I've had forever. Unlike the GM5 body (which. alas, has become discontinued, but is still available on the used market) it's still being produced as the "Digital 6" and is available for about 30 bucks.
This kit served me well throughout the trip. Image quality was perfectly satisfactory--enough so that I have had no qualms submitting some of the resulting images to juried gallery shows. Two samples are shown below. And by the way, although Theo took some really nice pictures on the trip using her iPhone, when we got back and looked at our results, she decided to buy a GM5 for herself. I'm not sure it's the perfect travel camera, but it's most certainly a very, very, good one.