Add class to views row using a template
Views itself will tell you which file to use as a template.  Go to the config page for the relevant view and choose Theme: Information under Other.  This will print out a list of potential templates; the template shown in bold is the one that is in use.

To get the node type, you can use the dpm() function of the devel module.  For example, if you have devel enabled, you can simply insert dpm($row) in the template file, load a page containing the view in your browser, and then dig through the output.