Got some inspiration on the "F for Flash" thing that's featured.
Here's my keybindings.
Q, W, E, R, D, F are quick-cast. On some champions, I put R on Quick-Cast with Indicator (cross-maps n stuff)
Slot 1 = S (For commonly-used item actives like Hydras for AD/Tanks, Hourglass on mages/AP champs)
Slot 2 = T
Slot 3 = Y
(other slots are default)
Yeah, that's about it.