this is such great info, thanks. I'm doing the Honolulu century. I decided to get the 5000 because there aren't any 2100's left and I would rather get a better bike than the one I wanted than a worse bike. The lbs also cut me a deal so the 5000 was only $150 more than the 2100 would have been. My helmet is a no name helmet, and it feels like it is too long but not wide enough. I suppose your right that spinning isn't cross training but I teach dance and I that works some other muscles. thanks so much for all your advice.
-Rachel