NASA's next generation of the Mars Rover project will be nuclear powered, laser wielding and weight about 1875 lbs. The new project is called the Mars Science Laboratory (MSL). Actually, I'm not sure where people got the idea that this thing has a laser capable of 'disintegrating rock at 40 ft", at least I didn't read anything of the sort on the NASA MSL site.

The rover will carry a radioisotope power system that generates electricity from the heat of plutonium's radioactive decay. This power source gives the mission an operating lifespan on Mars' surface of at least a full Martian year (687 Earth days). It's not quite a fission reactor, but still cool.

On-board memory includes 256MB of DRAM and 2 GB of Flash Memory both with error detection and correction and 256kB of EEPROM. Roughly the equivalent memory of a standard home computer. This onboard memory is roughly 8 times as capable as the one onboard the Mars Exploration Rovers.