As much as I agree that, indeed, a jazz collection is a personal thing and will grow eventually to encompass many if not all of the classics, this is of course the lame way out and furthermore is besides the point raised by Deus I think.
There have been collections, dots have been connected, cornerstones have been identified. So, why not build on that. Why invent the wheel all over again for yourself just because it's supposed to be a personal journey. Why not learn from the journeys of others, personal as they may be.
An approach that emphasises the personal discovery angle too much would negate any criticism or any historical overview. I think it may be possible to sum up some landmark/cornerstone albums/artists that together sort of define the landscape that is jazz; possibly on several levels. Take it in and get an overview, then move where your personal tastes lead you. I doubt whether I am up to calling out any specific cornerstones, but if we decide to label our shared subjective tastes as objective, we should be able to draw up something.
Probably I do not disagree with the quoted post by Jim that much, but the general tenor of "it's all personal and nothing we can do about that," is sort of going against my idea that this music and its audience are moving forward (wherever that may be).