This is a Lego NXT rover I built. It has independent suspension and enough torque to climb over the annoying threshold trim in every doorway of my apartment. It carries two Android G1s that will eventually provide stereoscopic vision and remote control via Wifi. Currently, it's remotely controlled by my Nexus One via Bluetooth.
I experimented a bit with adding four wheel steering, but it got rather complex. Skid steering works well enough for now. If the software side of things works out well, I may replace the wheels with some omni-wheels in the future.
I have some ideas for the stereoscopic vision. Mostly I'm interested in having a 3D remote viewing experience. For that, I'll need some sort of viewer.
I will also have to solve the charging problem. I'll probably start with the NXT Li-Ion pack. Then I'll have to build a dock.
All in all, this project is just getting started. But, I'm excited to have a robotic platform that has full mobility in my apartment. Also, the integration of Android will make development easier.
Check out the video below to see it climbing over one of those dastardly threshold trim pieces.