How much gray is too much??

Sorry, this is going to be long. Thank you to those of you that read this and comment!!

I'm not adventurous when it comes to decorating (or fashion, for that matter). We're moving next week to a new house, and I'm considering having most of the house painted different shades of gray. I like that it's a neutral, but it's not cream/tan. Really the only other colors of paint I like besides gray are blue, tan, or cream. Red is definitely out (doesn't go with anything we have), and I don't know that I've seen shades of green I'd like for a whole room. I like yellow as an accent in a room, but not as a wall color. Gray just lends itself to using any color accents in a room, which I like.

For reference, there are white baseboards everywhere and crown molding in most rooms (don't remember if it's in the bedrooms). Here are the colors in the house for now and what is potentially/definitely changing:

- basement - cream
- basement bath - currently dark brown, changing to blue
- kitchen - currently green with white cabinets, changing to a shade of gray and keeping white cabinets
- family room - cream, thinking of light gray
- living room - cream, not sure if it should change
- dining room - cream, thinking dark gray
- 1/2 bath on main floor - salmon-ish, changing to gray
- hallway on main floor and stairs up to 2nd floor - cream
- hallway on 2nd floor - cream
- 3 bedrooms are different shades of green and yellow - changing to different shades of gray
- bath upstairs - cream
- master bath - blue
- master bedroom - cream, probably staying cream for now

So, how much gray do you think is too much? If we do have the main floor painted gray, should that include the front hallway? And how far up the stairs should the gray go? Maybe just continue it and paint the upstairs hall gray, too?

Ah! Decisions!