So you've been hit by the collector's bug. I'm afraid there's no cure. Welcome to Collectors Anonymous.
So far, I have collected 4 more PowerBooks. I got another 2002 ‘15 I’m gonna put Jaguar on; 2003 ‘15 for Panther; 2004 ‘15 for Tiger and a late 2005 ‘15 PowerPC for Leopard.
Next year I will then begin collecting Intel MacBooks Pro’ up to the first 2012 Retina 15 inch.
Ye have been warned!