Where do you start: technology or organizational change?

I come across companies who think they need to improve their technology (and most often do) but discount the fact that no matter how good the technology they buy, it won't do much good until they change their organization - 'upgrade' their culture/processes/structure/skills/etc. On the other hand, I see some who use technology to drive the organizational changes. How do you approach this internally, externally, and with client/vendor settings?