I view the holy grail as being the end of my toy-buying quest, the last figure I am ever likely to buy. That is and always has been Fortress Maximus, for me; I've never been able to afford it, even when it was reissued. But with the release of Metroplex trumping him as the largest TF, I may now never buy Fort Max. The journey is more important than the destination.
Please put my grail down as a G1 MISB/MIB Bluestreak
Mine would be Takara Beast Wars Ravage, Maketoys Hegemon & Henkei Anniversary BW Dinobot.
My grail would be the Botcon 2011 Stunticon-job giftset, I know there is one for sale on the forums but it's currently too expensive for me to buy.