Not only is work-ex a bonus in a b-school, its a must. I say this for 3 reasons. Firstly, to understand the curriculum and the relevance of various subjects, one must have the background knowledge that serves as a base. This can only come from personal experience. It is easier to relate to a case study having encountered similar situations in the work-place. Secondly, a B-School is not so much what they teach you but more of what you want to and need to learn. This knowledge can only come once you have tried the waters in the corporate world. For example, an otherwise competent person found that he was not effective in resolving personal conflicts at the workplace. For him, a subject like Organisational Behaviour would be of moe importance than a person who realised that he needed more technical knowledge in statistics. Lastly, for the people solely focussed on gaining admission, 2 years of work-ex definitely helps your chances in getting into the top B Schools.