They were on sale a couple weeks ago at 200mp a piece.
Thats when i got all three, Overlord is really good i just played through that and it lasted me about 2hrs, and has a cool story. Kasumi is pretty good not as good as Overlord, but it's an extra character and her loyalty mission is around a hour long (on the ship you only interact with her like Zaeed, meaning you can't have a full conversation with her). I haven't played Shadow Broker yet but that is definitely the one to buy from what i've heard.
I'd say Overlord and Shadow Broker are the best, and if you have money get Kasumi if not you won't be missing out on much besides a pretty good SMG.
" I think it'd be hilarious if the Rachni just roll in and exterminate everything during the ending ten minutes of ME3, mostly because bioware wrote that dialogue in such a way that only charles manson could have exterminated them. "
If only that was going to be one of the alternate endings. "
Thats what i want too, sort of like the end battle of LOTR 3, where those green ghosts roll in right when everything is fucked and just tear shit up.