Garmin Edge 830

The Edge 830 is an excellent bike satnav. It will calculate a cycle-friendly route to a destination - or you can plan your own route - and get turn-by-turn directions while you're cycling. Don't expect it to always pick the best route (the the one you would have done) but it will get you to the destination when you haven't planned a route in advance.
It also works as an advanced bike computer, displaying and recording all your stats as you ride and will also show you an elevation profile so you can see whether it's uphill or downhill ahead. There's Strava integration, and it's great as a training device.
It's compatible with a range of ANT+ accessories, including heart-rate monitor, speed and cadence sensor and more. There's Bluetooth and Wi-Fi so you can sync routes and ride stats to your phone, and also get call alerts and text messages on the Edge's screen.
The screen is much better than earlier Edge models and is very easy to see when the sun is shining on it. The touchscreen also works if you're wearing gloves, and in the rain.