Presentation is important, but it must play a subservient role to the content. Content is king.

I've noticed that very few good games have bad graphic design and typography. It's not an absolute, but, for the most part, people who put a lot of care into the words on the page ALSO put a lot of care into framing and presenting those words.

I am actually more aware of readability these days as my glasses turn to bi-focals. So in that respect, layout is very important.

I am finding out that I am not liking the "parchment background" style of many of the 5e books that I have seen. Also lots of graphics all along the margins ...pretty much saying the text is laying on top of a cool background really just bloats the size of digital copies unnecessarily.

For example, I think 1e Stars Without Number is preferred by me mostly because I feel 2e has gone in that layout direction (and also why I find it hard getting into Eclipse Phase and even Star Frontiers for that matter as an older example).

I meant to add some good layouts that seem readable to me.

I think the older version of OSRIC is very readable (and the green hues for the tables really help). I also really like #VSCA 's layout. The Illustrations are really well done.

@Alex Schroeder has a love for Tufte layout that I equally enjoy. Seeing the style in @Jeremy Friesen's blog warms my heart.

When I come in contact with a new game, it's usually because someone else makes me play it, or because I hear other people talking about it. But if I have to go through a shelf looking fore games, the graphic department is definitely what gets my attention first, and it can make me look at a game rather than at another.
Good illustrations catch my eye, and I *tend* to associate cheap/bad graphic design with amatorial authors and lower quality games. I know it's not always like that, but then again, I tend to hear about good games from in other ways

I find that anything that interferes with readability or utility turns me off, hard. I'll make myself work through it if I think the content worth it, but I won't be happy.

I can appreciate good layout in a bad game, but it is unlikely to overcome a bad game.

Thankfully, as observed above, most good games care about layout, so do it well.

TL;DR: I'll suffer a good game with poor layout, but not a ooor game with good layout.

There is some influence on me by graphics, but I really hate games that have put so much graphic content in that it becomes filler.

A Good graphic layout, if graphics are used, should act as mental mnemonic that lets you remember where a specific section or important piece of data is. This eliminates the need to memorize page numbers or look for such in an index or table of contents.

They should, if there is a setting involved, represent the setting in some way (such as architecture, clothing, etc.) to give a feel for the setting. They might also give a feel for the setting, setting tone, when possible.

That said, I don't react badly to low graphic high text material.... but I do react badly to material that is full of way too tiny text or has graphics bleed that obscures/covers the content.

I have rule sets that have been typewritten on stencils for reproduction. I hate it when graphics displaces the information or there are pages of images that do not value add. I would second Joseph's approval of graphics that enhance finding data but while I have seen plenty of catalogues that do that I can't ever remember seeing it on a RPG rules set. also things like the finger tabs you find in bibles.
I wish production companies would specify the kind of lay-flat binding that O'Reilly used to use on their reference books.
I do really think that the preponderance of multi volume, high production value, glossy, hard bound rule sets is actually an impediment to getting new people started in role playing or even in a particular rules set.

Aesthetics aside from being able to denote the game state is unimportant to me. I want to look at the board and pieces and be able to easily discern the game state. Beyond that, it does not influence whether or not I buy the game.

I do appreciate a good production value when it comes to games. However, I find that even games with high production values sometimes make it hard for me to identify the pieces out of the box. An example is Fortune & Glory. The game is expensive and one reason is the high quality of the components. It uses thick card stock and miniatures for all of the pieces. The one difficulty I have is that all of the player pieces are grey. When looking for my particular piece, I find it not easy to discern which of the grey pieces is mine. I have added stickers to the bases with writing to assist in discerning which piece is which. I do understand that often people paint miniatures. I don't feel I should have to do that in order to be able to easily identify the pieces.

It varies. Some games with dirt cheap or no graphic design are great, and the lack of fancy layout suits the game. Some games have technically great graphic design, yet something about it puts me off. Generally, though, when done right, I do think it enhances the game. Edge of the Empire would not be the same without gorgeous Star Wars art. In Shadowrun, and cyberpunk games in general, the aesthetic of the game adds a lot to the atmosphere. That said, in many ways I might enjoy the more primitive layout and art of WEG Star Wars and '90s FASA Shadowrun more.

"How important are the layout, graphic design, and typography of a game, as distinct from its playability"

The key here is playability,

I want to be able to read the cards in whatever zone they need to be read in. For example if I only need to read the cards in zone one (my hand) then the font can be small and there can be lots of flavour text and information on them. If I need to read them in zone 4 (the comunal play area) they better be large text and or symbols that I can easily see from across the board.

Now as for distinct from playability, for board games I care more than I would like to think. I've been playing a growing number of prototype copies of games as I get more involved in tabletop game reviews and playtesting and there's a distinctly different feel and level of enjoyment from playing something with abstract functional components to playing something fully artistically realized. Graphic design, layout and typography should tie everything together and should express the theme of the game. Distinct styles should be used for different elements of the game to separate them during play. And more of all none of that should affect playability (to bring things full circle).