Google Scholar ranks journals by how often their articles are cited. Of their most recent list of 20 most influential Urban Studies & Planning Journals, Hunter's subscriptions include at least 20 years of full-text for most of them.
Urban Studies Abstracts is a great source for information about articles in these -- and hundreds of other -- relevant urban studies journals. Database also includes abstracts from legislative groups, research institutions and public agencies on all aspects of urban studies. List of journals included.