For me. DLCs are probably the biggest gripe of modern gaming. Well I say modern. Rather in the last 5 years or so. Let me explain what I mean. To me it feels as if when you buy a game, you aren't actually buying a full product; you're buying a product about 80% done ( Fallout 3 springs to mind straight away). or in some cases you're spending £10 on a few maps *cough * CoD *cough cough* and it just doesn't seem right. Now don't get me wrong here, I know some of you will say "but expansion packs have been around for ages!" Yeah. that's the thing EXPANSION PACKS! Take for instance Red alert 2. you have an entire game with a whole story line to play around with. With the release of Red alert 2: Yuri's revenge you get not only an entire new faction, new maps, new story line and new units for both the Allied and the Soviet. the same could be said about Age of mythology (by the creators of Age of Empires). Even Call of Duty 4 (when it felt like Activision were the good guys) gave away the maps for free on the PC.
So then I look at the games post 2009 and they are all filled with DLC content, though might not be expensive (say £5 or something) it feels as if you are missing out if you don't have that special player skin everybody is talking about.
Another issue is when the developers say they would of added the content/put it on the disk but they didn't have time to implement it or it wasn't finished in time to be put on the disk.... And then they charge for it.
(And yes for the references to the games above I did look at my game shelf of which ones I have been playing recently)