The small print states the offer can't be used in conjuntion with any others, which rules out discounted and DoTW downloads. This, along with the Indie games not being included, was confirmed by somebody at Microsoft. I'll see if I can find a link.
Edit: I can't find a link to the quote, but...
It's worth noting that any discounted or Deal of the Week DLC does not count towards the 2400 points you need to spend for this offer.
Zombie Nightmare and Lair of the Shadowbroker are certainties for me. Just need to find a way to spend the other 800 I'll get back for free. Bargain.