The Exec Producer of The Walking Dead stated that 10 years of shows won't be enough to tell the story. The network AMC loves the show and the ratings are great and increasing as I understand. I would say the show is going to be around for a good while.
Once thing is for sure no one is safe (acting job wise) on this show and that will play well for the story in the long run. People can get killed and new survivors can fill the void. Making for a fresh line of plots and sub plots. Not to mention the back story of the characters as well. So without spilling any season secrets for those who haven't seen the show or caught up yet on past seasons fire up the DVD player, DVR or Netflix and start watching. You are missing one of the best shows on TV.
3rd best, right after Breaking Bad & Mad Men. But BB is winding down, not enough characters to keep the story alive. And Walt will self destruct soon or be assassinated.