I think grey gives rooms a really classic feel and it's easy to work other colours with it. Blue - especially turquoise and duck egg hues - is probably my favourite colour. It's brightening, refreshing and energising. Sunny yellow is just so cheering, especially on dull days.
Colors used in my room:
White, grey, blues, yellows
Tips for using color successfully:
Follow the rule of three! Repeat the colour at least three times in your room to make it look cohesive as your eyes move around the room. Don't be afraid to mix up the patterns and prints your colour(s) feature in.