All of the fallout 3 dlc's were at least worth the money with all but one being very good, the borderlands dlc where all fantastic and more of what a sequel should be a lot more story to go with the great gameplay and characters, oblivions dlc was pretty good on the ps3 knights of the 9 was an interesting little side story while shivering isles was simply amazing. Most good games have fairly good dlc which shouldn't be a surprise.
MZ was worth the 10$ just for the katana and samurai gear. Someone at gamesas heard me scream out in my head "this is great where is the katana though" I normally hate the way spaceships look in games. (ME and Bulletstorm) Mass effect is so sterile and bleak looking it makes me cringe. I also enjoyed all fallout related dlc thus far but part of me wants a game breaker dlc for the last one. One that gives you access to sweet equipment and lets you fool around with the game now thats its complete,gameplay over lore anyday. I just need either a katana and or AK-47 family variant of the Chinese assault rifle,I don't care how they get it into new Vegas just that they add them in.
Some of them havn't been that great (Zeta), but Bethesda make a valiant effort to give players good value for money. As long as they don't start bringing out things like 'Alternate appearance packs' then I won't complain.