A light yellow would be lovely. It sounds Iike it will be a great space!

White would be clean and classic. A pastel yellow, pink or turquoise would look nice with the gray (in the pic you posted the gray has a lot of blue in it, but I remember it as more neutral from other pics and IRL). Or you could go for something really bright, like vermillion.

Personally I would go with white, but I tend to be blah in decorating. Anjou pear would be a great complimentary color if you want to add some zing to it.

The BM website shows a bedroom in anjou pear with an accent color called silhouette which is a dark grey. The title on the website is delightful green bedroom.

I love bold colors but here I'd go with Benjamin Moore snow white, which has some silver undertones. Good luck!

Another vote for BM Snow White! Or a very light grey, but you'd have to have the cab door in hand and be very careful with that choice.

How much wall square footage are we talking here? Do you have lots of wall cabs? Is there a soffit involved? I would do the Snow White and really wait to consider BS until granite is chosen.

White. Others may disagree but I would prefer a warm white next to all that cool gray.

white with a drop of bluish gray.

Make sure to get a sample jar and paint a big sample on the wall, observe the color in different hours of the day before making your final decision.

I like the white with them, and that leaves your accessories open to all kinds of color choices. If you want color, yellow, pear to lime green, blue -- actually, there are probably shades of just about any color that could work with grey. Is there a color you like to have around you or create the mood you want for your kitchen? If not, why not do a white that reflects the undertones and then get the other elements in place. You may love the calmness of it -- like the IKEA photo and probably the display, but if not, paint is easy enough to change if you find that is too plain.

I love cream and gray together, so I'd strongly consider a cream/gray/white color scheme. Then, when more liveliness was desired, almost anything color could be brought in as an accent. How about fuschia for summer? :)

I would love at least one wall or area in a coral-pinkish-red against that gray; not knowing what sort of color personality you are makes it hard to suggest.
White would give a nice crisp feel.

I have been in love recently with pale blue/green/yellow/tan mixes for tiles and think they look great with grey. You'd have to be sure they were cool tones for this grey.

Do you like the picture you posted? It really has the elements you have described in your post, maples floors, white counters, is it your inspiration? It has warm white walls and a citron tile backsplash. I think warm white would be great.
You could add tile with a color or it too could be white and you could have color as an accent which is easier to switch in and out. Some of this depends on your layout and how much wall, backsplash there will be. Can you post your ktchen pictures from the IKEA planner?