Hey guys, I'm playing through mass effect 2 for the first time, and I'm curious as to when I should play the dlc.

I'm most definitely going to play through it multiple times, but I do want the most complete and cohesive experience I could get.

So if anyone could give me advice of when to go about this, without spoiling the storyline, it would be greatly appreciated.

Kasumi is best done early because she comments on stuff and what not. 

I bought it all when I was about 3 hours into the game, they just integrate into your mission log when available. 
 
P.S Can't wait for the new DLC  :D

None of the DLC ends up spoiling  other parts of the core game, do they?

Goes without saying that Arrival will be best left for POST-game saves :P Though I'm pretty sure that it can still be played before the main stories up, after the Horizon mission.

The only reason I'd ever suggest playing Lair of the Shadow Broker during the main game is because after you beat it you can respec your squadmates and there is no other way to do that in the game, a feature which becomes rather useless if that's the last mission you do. Otherwise I'd suggest playing it at the end. The other DLC can be played whenever, though Kasumi is a good one to do right away because she's a good teammate and it gives you a pretty mean SMG.

Do whatever is available before Horizon (a forced story mission) this means Kasumi, Zaeed, Overlord. 
There's some weird behind the scenes math related to what kind of missions you do and when you do them - you may end up locking out certain options without realizing it. (it's very hard to explain w/o spoilers) Focus on loyalty and recruitment missions - also in terms of Shadow Broker, do L'Aria's quest line on Illium FIRST, you lock them out by giving her the data on your first meeting.

@drag I'm in the exact same boat. I missed out on the DLC deal by a matter of hours, simply because I thought it was on sale until the end of the promotion and not the end of the day. So now I feel like as soon as I buy it it'll drop with the forthcoming DLC. Haha.

But anyway, thanks for all your responses. I think I'll probably leave the shadow broker for last and mix in the other dlc as I make my way through the story. I just finished the Horizon mission for clarification.

By the way, is there a confirmed release date for the final DLC?