Where to live in Zagreb?

Hello,

I am moving to Zagreb in late September and will be looking for an apartment. I am going to be a researcher affiliated with the University of Zagreb and would like to be located close to the both the Political Science faculty and the Sabor. I would also like to live in a fun and active neighborhood with good nightlife. Can anyone recommend a neighborhood that I should look into?

Also, others have recommended that I use a rental agency to find an apartment. Does anyone have a recommendation for an agency that is easy to work with?

Thanks,
Andrea