I still have my WoW discs but I have stopped playing I still need to pick up lich king and roll a new character, but I am wondering if it's worth it to start playing again?

Yeah, sure.
 http://www.giantbomb.com/world-of-warcraft-cataclysm/61-27896/the-giantbomb-server/35-431745/#19

I'm going to say yes only because I went through this decision process the last week or two and just decided today to start playing again.

It is, but don't bother with the discs. So much has changed, that patching the game will replace almost all of the data anyway. My advice is that you log into battle.net, and download the client from there. Took me a few hours, but it installed the game all the way up to the latest patch with one click. 
 
Much less hassle. 

before you install again, make sure your account is properly linked to battle.net
 
then you can register your discs (aka Keycode)  to the account and download a digital copy whenever you want.