Sadly, the answer to the above question, "When do my favorite cable shows return?" is not for awhile, at least for some of them.
Kristin at E!Online has done a nice job summarizing when most of the major cable shows will be coming back for your viewing pleasure. Though most of these shows have been summer shows in the past, the strike has pushed many of them to either Fall '08 or even sometime during the first half of 2009.
Here is what is known about the return of a bunch of shows, separated by network:
HBO
Entourage - September 2008
True Blood - This is a new show from Alan Ball (Six Feet Under), also premiering in September 2008
Big Love - Early 2009
Flight of the Conchords - Early 2009
Tell Me You Love Me - Summer 2009 at the earliest, though nothing is official
Showtime
Californication - September 2008
Dexter - September 28, 2008
FX
The Shield - September 2008
It's Always Sunny in Philadelphia - September 2008
Damages - Early 2009
Nip/Tuck - Early 2009
Rescue Me - Spring 2009, with 10 minute minisodes this summer
Dirt and The Riches - no dates for either; both might be gone for good - especially Dirt
Other Networks
Mad Men - returning to AMC sometime in July 2008
Kyle XY - returning to ABC Family in January 2009