Around here, at least, after the initial price shock we had a bunch of bikes on the road. As the prices have crept down, and the weather gotten cooler, however, the numbers have fallen back to the usual. I don't think motorcycles will ever have the acceptance here in the US that you see overseas, due to our somewhat safety-obsessed culture, and the lack some of the advantages for motorcycle commuters (filtering through cars, reduced rate parking, etc) that are present in Europe.
If gas prices continued to climb, it wouldn't surprise me to see, rather than bikes gaining acceptance in the US, bikes becoming a target for heavy fees with an eye towards effectively banning them since they're perceived by the majority of folks as unnecessary 'toys' and unsafe to boot...
-S5