Leica DISTO D2

Good value. Great features and functionality. 
The D2 offers multiple modes of measurement that are useful for many different kinds of projects: distance, min/max, permanent, stake-out, add/subtract, area, and volume, and it includes painter and Pythagoras functions. An intelligent endpiece enables you to measure accurately from outside or inside corners, including diagonal measurements. The D2 calculates area and volume, and remembers the last 10 measurements taken. And a back-lit LCD screen makes it easy to read while you're on the job. 

Intelligent endpiece for corners and rough openings. 
The D2 measures from its base by default and can be configured to measure from the front. You can also flip out the intelligent endpiece to 90º to hook onto outside corners or extend the endpiece fully for inside corners, and it will automatically measure from the endpiece when extended. Combined with the Min/Max function, the endpiece allows you to get the tool all the way into corners for accurate diagonal measurements. 

Small, simple, powerful. 
While the D2 only weighs 3 ounces (100g) and can easily fit in a toolbox or your pocket, it has a simple-to-use interface and powerful circuitry in a compact casing with IP 54 rating, protecting it from dust and splashes of water. The interface is perfect for casual, as-needed work at home, but you can rely on the D2's accuracy—the intelligent endpiece connects directly to the circuit board.  

Best bang for your buck. 
If you'll be taking measurements often enough indoors to require precise accuracy, and if you need extra functions for different types of measurements, like corner measurements, then the D2 is a great choice for functionality and value. 

Want to learn more? 
DISTO Technology Overview
10 "Nice to Have" Features in an LDM