Best Blofeld?

The Telly Savalas version is easily the best. A sinister and cunning mastermind who wasn't afraid to get dirty and involve himself in the action.

Donald Pleasance.

So committed to his craft he even stayed in character and kept filming the scene even whilst that bloody moggy pissed on his lap.

Telly Savalas. He was excellent in OHMSS. but then that film probably ranks as my favourite of the series.
Then Donald Pleasance who was creepy.
Waltz was good but the film seemed to overlook the character.

Donald Pleasance.

Telly Savalas often got slated as an actor, even by dear old Clive James (RIP) but his Blofeld was brilliant. A great combination of silky, steely, menacing and shrewd, and his revenge mission on Bond is the most chilling, as well as moving, ending to a 007 flick.

Even the Craig films failed to match that - Waltz seemed just like a bitter little man - and the other Blofelds were a bit too camp, much as I liked Gray in particular.

Pleasence is iconic.