I think a nice blue would look very nice with those choices. Have a look at BM Smoke 2122-40 or something along those lines.

benjamin moore whites - Google Search · More Info

A nice light green might also be nice - just a hint of colour in your paint would be nicer than plain white IMO. If you look at BM - they have a whites collection with lots of choices for just barely coloured whites - blues, greens, greys, pinks, yellows. Then you'll need to test them in your room to see how they look with lighting in there etc.

Then you can repeat that same tone in your choice of accessories and towels.

benjamin moore whites - Google Search · More Info

benjamin moore whites - Google Search · More Info

I agree, use a blue or green depending on which one you like better. I just did a bathroom with matte white and gray slate and used BM 463 - Woodland White at 50% which is a pale green. I also sampled Sea Wind OC-139 which is a pale gray/green.

Here is another one I used recently that I really like.

BM Green Tint - 2139-60. Just a hint of green - a very pleasant colour.

Green Tint 2139-60 | Benjamin Moore · More Info

I hear ya both - I have a lot of that color family already in the house (living room is Palladian Blue, another bathroom is 50% Sea Salt). Sad thing is I'm kind of tired of those colors and am looking for something new, otherwise I'd totally agree with both of you. I still may end up there!

Then maybe just a gray toned off white? Classic Gray and Swiss Coffee are popular. You could still do green or blue/green towels with that background.