I love cameras that let you swap lenses. I love the gadgetry and the nerdery about them. But not everyone does: many people simply want a camera with a good zoom that takes genuinely high-end shots. This desire used to be fulfilled by so-called 'bridge' cameras: compact-size snappers that bulked up a little to allow for very large (40x) zooms. The problem with these cameras is that the quality of the final image has never compared well with cameras using standalone lenses. This is usually because the sensors and lenses used by bridge cameras let a lot less light in. Sony's 20-megapixel RX10 is a high-end attempt to fix this. The camera has a large (1-inch) sensor and a fixed 24mm-200mm zoom lens that holds an F2.8 setting from one end of the zoom to the other. This is actually quite a big deal: no one has made a fixed-lens camera that can do this before. The results are very impressive: this camera takes some great shots.
The RX10 has high-end features such as a flip out LCD monitor, wifi and NFC (for Bluetooth connections). It also has jacks for external microphones (for video) and headphones. And the build quality is high, with sturdy metal and rubber making the device more robust than a plastic equivalent.
The only thing I didn't like about this camera was its electronic zoom, which Sony has made controllable as a manual ring on the lens. It's quite slow and feels awkward, which is not what you want when trying to focus quickly.
It's also quite pricey, though perhaps not when compared to premium fixed lens rivals without this camera's zoom capabilities.
Overall, this is very high-quality stuff and probably the best all-in-one camera you can get.