When ICs are vertical, I guess it's normal to have the notch at the top- pin 1 top left.
But if an IC is horizontal- as is often the case with a long breadboard across one's desk- is there a convention for placing the notch at left or right?
I keep all ICs facing the same direction with pin one on the bottom left.
I really haven't seen anyone reverse this in any of the images I have seen since 1974
Hi, its sort of an unwritten convention, horizonal left on protoboard.
Even PCB assemblies I find majority try to keep all the IC's in one direction, either left or right in direction, in PCB it has to do with ease of track routing as to how IC's are oriented.
Tom.... 
JimboZA:
When ICs are vertical, I guess it's normal to have the notch at the top- pin 1 top left.
Normal, but not always practical.
But if an IC is horizontal- as is often the case with a long breadboard across one's desk- is there a convention for placing the notch at left or right?
The convention is to keep them all the same way round. But if the board gets turned through 180o, all your ICs will be facing the other way.
I've an old board on my desk (Seikosha) with, if I keep the silkscreen the right way up, the power coming in from the right and all ICs with their notch on the left. But what do you do if you need to have some vertical and some horizontal? :~
Henry_Best:
But what do you do if you need to have some vertical and some horizontal? :~
Well, then you turn it 45 degrees and compromise 
You're up early- off the the tennis?
I try to have them all the same - stay consistent.
JimboZA:
Henry_Best:
But what do you do if you need to have some vertical and some horizontal? :~Well, then you turn it 45 degrees and compromise
But where can I buy a 45o breadboard and some 45o strip-board?
You're up early- off the the tennis?
Nope. I'm an insomniac. I'm up late! Tennis is boring.
Hi, I know make all the IC's you use square, with pins on all sides.
Tom......... (Tennis, go Aussie Aussie Aussie, oi oi oi.)