I don't typically pay a lot of attention to what DLC is out there - it's frequently nothing that interests me much, at least not at the prices they charge.
The ones that interest me the least tend to be the ones that add a new zone or quest chain - while on paper I'm interested in more content and that seems the most worthwhile thing to be spending money on in a game, in practice they either get released so early on as to be a blatant cashgrab and should have just been part of the core game, or they get released so late on that I'm done with the game and don't really feel like firing it back up just to go explore that one short quest or area.
I think the one that's irked me the most though are the characters for Borderlands 2. I mean, £8 for a new character? I could maybe understand if the characters in that game were really deep and complex, with each choice opening up a load of playstyle options and different ways to build your character - and clearly took a lot of resources to plan and balance. But really, the classes in that game are all play pretty similarly, the talent trees are pretty simplistic, and no way is any one of them worth 25% of the cost of a brand new AAA title.