I think the important thing to note with the 4/3 vs. micro-4/3 commentary running here is that the two standards are designed to fit different spaces.
The 4/3 system is designed for the traditional dSLR camera space. The micro-4/3 system is designed to allow lens-swapping in the high-end P&S space (and hopefully eventually across the entire P&S space if it takes off). The fact that you can use an adapter to put a 4/3 lens on a micro-4/3 body means you can actually use top-end lenses on your incredibly light-weight body if you should choose to do so.
Olympus, due to the smaller sensor size of 4/3 (which they understood going in) has already started focusing on increasing sensor *sensitivity* to improve image quality, while most other manufacturers are instead still focusing on more mega-pixels, which often has the side effect of resulting in a worse picture due to increased noise.
The 4/3 system is designed for the traditional dSLR camera space. The micro-4/3 system is designed to allow lens-swapping in the high-end P&S space (and hopefully eventually across the entire P&S space if it takes off). The fact that you can use an adapter to put a 4/3 lens on a micro-4/3 body means you can actually use top-end lenses on your incredibly light-weight body if you should choose to do so.
Olympus, due to the smaller sensor size of 4/3 (which they understood going in) has already started focusing on increasing sensor *sensitivity* to improve image quality, while most other manufacturers are instead still focusing on more mega-pixels, which often has the side effect of resulting in a worse picture due to increased noise.