When the m43 format was announced I was shooting with the Canon 30D and carrying the Canon G10, Sigma DP1 and sometimes the Zeiss Ikon. I used the 30D for 'quality' photography with the 17-55mm f2.8 zoom and the smaller cameras for more discreet work and video. I immediately saw m43 as a way to replace DSLR with zoom and the compacts with one camera, but it has taken until this year for this to happen.
The OM-D is at least the equal of the 30D in image quality and the upcoming Panasonic 12-35mm f2.8 zoom will cover almost all of what the 17-55 did. In the meantime I had fallen in love with the relative compactness of rangefinder shooting, and I realize now that my love of rangefinders is not about the OVF or 'seeing outside the shot', but having a small and fast body with excellent image quality. The OM-D gives me this now, replacing the DSLR with zoom as well as a rangefinder with primes for many situations.
I still love my other cameras. The M9 is my all time favourite camera, although often a bit heavy and expensive to carry all the time. This winter in Melbourne has been terribly cold and rainy, and I've had to stow my camera under my coat or in my bag with a feeling of paranoia every time it starts to rain. This is another thing that has prompted me to get the OM-D, with its weatherproofed body.