Color alone won't do it. The trick is in the lighting.
Definitely not any florescent lights.

Avoid anything which will create harsh shadows, in both color AND lighting.

Now for my favorite color so far, it is the Behr paint LILTING LAUGHTER. It sits faintly on the wall, and is a soft hint of peachy flesh tone. It goes well with white, and with natural stones in a wide range of colors.
Get a sample 8 ounce jar of it in flat finish at Home Depot, and try it out.

There should be lighting on the sides of the mirror not just from the top.

Pale lilac/lavender. Check out Benjamin Moore "Slip".

Here is a link that might be useful: Benjamin Moore

I did not do this on purpose but SIL pointed out why she loves our guest bath so much - the lights - on either side of the mirror have handblown amber glass globes.

I actually considered when I bought them that they might not give enough light and decided to go with them because I liked them aesthetically and figured a guest could deal.

SIL said they make your skin look amazing - very flattering. I checked it out and she is right. It is very flattering and kind mimics outdoor filtered sunlight.

Dang, I don't think I'll be able to do lights on the sides. On the mirror wall, I think it would look awkward because the sink is off-center from the cabinet (weird angles in my bath causing the countertop to angle, therefore forcing the sink off-center if I want a stack of drawers in my cabinet--for both, separate vanities).

But I can check into the amber coloring. Thanks!

I looked at tile for the first time yesterday. As usual, too many choices! I love so many different colors/combos. Can't decide which way to lean.

As far as what paint colors look best, I'd look to your wardrobe. So for me, pale blues from hyacinth to aqua, and soft pinks from peach to orchid. I can't wear yellows or yellow-greens, so no yellow or green paint in my baths.

I replaced the vanity lights in all of our bathrooms with Reveal lightbulbs a few years ago -- instant flattery!

I would think shades of pale pink would be flattering.

Thanks for the replies and ideas.

And, in thinking of lighting--I'm now thinking of a solar tube to get more natural light into the 1-window bathroom (north-facing and frosted glass at that).

lee676 can you name a specific brand and model number of the bulbs you refer to please, thank you!

Ohhhh, the solar tube! I dearly love that concept, and I would have them if I could convince DH to let me drill another hole in the roof!!

They even make them with one hole and twin solar tubes. If you have back-to-back spaces it would be an easy way to light two for one hole. Absolutely a good choice in my book.

catkin, there are so many of these, what wattage/brightness do you need, and do you want compact fluorescent (CFL) bulbs that retrofit into lamps designed for incandescent bulbs, or traditional fluorescent bulbs that are long tubes usually 2' or 4' long? There are also an assortment of CFLs that fit into sockets designed specifically for CFLs. If you want dimmable lights, you'll need bulbs (and if separate, ballasts) designed for them.