There is a slight difference in the approch to answer this 
question for a Fresher and Experienced Ones.

Fresher's Answers:
The role which am being interviewed for is something that I 
have been looking for and I have worked hard to attain the 
Domain expertise on it and I am looking forward to prove 
myself if I can a chance and not only that there is a lot 
of learning aswell that is required once I join this 
company and I am eager to learn and grow along with the 
company and this company being a world class organization, 
I belive that I can get a fair chance to prove myself and 
the qualities that I have with in me to dedicate myself 
with the work and the company culture and a zeal to learn 
new things and more over planning for a long term 
commitment makes me one of the best guys to work for this 
company.