KOI-314c is a recently discovered Earth massed planet. Its density is also quiet low considering that the planet’s diameter is 1.6 times the Earth. It was discovered using the Kepler telescope, which detects the dimming of a star as the planet orbits in front of it. The press release I linked above has tons of information about it. Badastronomy also has a great general summary here.
Speaking of planets larger than the Earth, but smaller than Neptune, the most common types of planets to be discovered seems to be those. Thanks to Kepler, we are getting a better idea of the size distribution of planets, at least those that orbit close to the star. Of course, the planets are not going all going to be of the same density. Some might be rocky, others could be icy, and it could also be gassy like Neptune. Based on the measurements of the densities, most of them seem to be the gaseous kind. Another noteworthy point about this discovery is that the Solar System has no planet of this kind even though it is extremely common in the universe. Of course, this doesn’t make the Solar System special, it just got the way it is by the laws of physics and chance. Still, it is a cool fact, and it shows how diverse star systems and planets are.