Gran Turismo 5 is without doubt the reason I decided to get a Playstation 3. After numerous delays (spanning nearly 5 years) I am delighted to note GT5 is now set for a UK release on the 24th November!
As far as I can tell the cheapest place to get hold of a copy is by pre-ordering from HMV. Aside from getting a 25% discount on the RRP for GT5 you will also receive exclusive codes giving you access to the Audi R10 Tdi and the Honda NSX GT500 stealth models.
For full details please view the HMV Gran Turismo 5 offer page.