I can't tell you whether or not DLC is general is worth it. It varies from game-to-game and person-to-person. The DLC for Fallout 3, for example, added entire areas and stories to the game and, with Broken Steel, extended the main story. An example of companies using DLC to get as much money for as little effort as possible would be Resident Evil 5's multiplayer "DLC". With that, you were paying $5 for a small piece of code that unlocked content already on the disc. Unfortunately, like with most things, the bad significantly outweighs the good.
So, the best thing for you to do, TC, is to do a bit of research on DLC that interests you and determine whether or not you're getting your money's worth.
We got so much in common, except when it comes to rhyming
She feel like lyrics are so intrusive, but I feel about her the way she feels about music
She's cute, she don't like the words, she just likes the beat and I'm thinking me too