If we are to believe Microsoft and Sony, this console generation will last until around 2015. Capcom, on the other hand, are not so sure and in an interview with Games Industry.biz their European boss David Reeves says that he expects new consoles within the next 2 - 3 years.
Worth noting is that David Reeves was the head of Sony's European Computer Entertainment-division for 14 years. So perhaps we shouldn't dismiss his theories straight away.