Shouldn't the question be more which angle of view will be useful to you?
I am facing a similar quandry mysef: have spotted a 28mm and 35mm PC pair of oldies that could be useful, but the question, for me, has more to do with which will represent a lesser waste of money. Neither will bring me a bean, to that I am resigned, but having already had a 35mm one for a long time and then traded it all away, I know 35mm always felt too narrow... but, 28mm doesn't (apparently) cover very well on digital, and as far as I can discover, Nikon's new 24mm Tilters aren't all that hot either.
Maybe Canon's the answer: 24mm and 17mm. But not for me, I'm afraid.
They do this on purpose: it's a plot.
;-)
Rob C