Steam currently have LA Noire at 75% off for the Midweek Madness Sale which comes only weeks after the recent price drop for LA Noire on the AU Storefront.
The Complete Edition can be picked up for $14.99 (or just under $10 AUD from the UK storefront, $7.49 on US)
& The DLC Bundle - $4.49 ($2.99 on US)
With the Steam Summer Sale only a few days away (possibly starting this weekend) I wouldn't take any risks and wait any longer to buy the game because games that go on sale for over 50% off 1-2 weeks before the big sales don't usually get discounted as much during the big sales.
Sale ends 3AM Friday (AEST) (Possibly 9AM, sometimes they extend it 6 hours)
Would be a crime not to buy at this price.