First of all, one-off deals on single games don't cut it for me (ie. Blur). The TRU $10 Halo card was OK, but stores generally had a very YMMV selection of decent things to get with it (and otherwise getting $10 off $50 or $60 games isn't such a great deal).
By far and away the best sales of the year were the 2 (or was it 3?) Blockbuster B1G1 free ($14.99 and under) sales. Combine that with some ahead-of-the-curve price drops (Beatles Rock Band when it was still $30-$40 everywhere else in the earlier sale, and God of War III when it was still $30-$40 everywhere else in the later one, etc) and it was an awesome sale. I still have a pile of games here that I haven't touched from that sale. Oh, and for the most part the big games were available in mass quantity at most locations so any CAGs paying attention and going the first few days, at least, could get whatever they wanted.
And every game that I got was near mint/complete - they had a lot of rental overstock on some of these games and so they could often be found practically brand new (at least no worse than a Gamestop gutted "new" game).