This is what I have been hearing from vendors recently:

Eastern Europe : will draw a great deal of attention in the coming years since the region now has a good IP infrastructure, and a number of digital TV providers already exist in the market.

Japan: will grow very fast due to favorable environment for deregulation, consumer behavior, competition, and access to capital.

US: will continue to be stymied until carriers switch from non-scalable Microsoft platform!!!!

Western Europe: already well addressed by vendors and service providers

Other new regions: China and US will become hot markets with the predictable migration of cablecos to hybrid cable / IPTV offerings.