This free local paper has a great free classifieds section, the best coverage of the local music scene, and good reporting on local news stories that aren't covered elsewhere.
It comes out on Thursday night and if you are looking for an apartment or a job in most North side neighborhoods, this is the first place you look. The Trib is better for regular jobs, but more edgy jobs are found here or on craigslist.
They also have a personals section that is great fun to read, if that sort of thing amuses you.
They have an online version of the Reader than can be useful too.
http://www.chicagoreader.com/
more