Ok, as an audio engineer I would REALLY love to see the photoresistor have real world functionality. Maybe make it so that when you drag a lamp or LED near it, an option appears to couple the two together into either a VACTROL or an OPTOCOUPLER, at which point it would function like a subcircuit or black box element. Ports would become available for the light source connections as well as + and - from the photoresistor. And it would be assumed to be inside a light-tight box so that only the light from the light source (again, this would be the LED component, the LAMP component, and maybe you could also add an EL panel component...that would be cool in general for this purpose as well as other things) would be capable of exciting the photoresistor. And as per normal real world, the resistance would swing from high (1M or more) down to low (a couple of hundred ohms at the most) when the light level rises.

Ok, now, I would also like to suggest (and second a few others here) that an LM317 would be good, Audio and power tubes would be fun, some specific op-amps instead of just a generic one would be cool (with real world characteristics...and I know that these can be made as subcircuits but still...), and also an LED bargraph display would be sweet.