If you only have room for one shadow compact to carry around, pick a combo of neutrals that will compliment any outfit. I'll only wear shadows for night outings, but one of my favorites is Beauty Addicts' ExpressEYES ($35). The brand is based on making different "moods" or looks with each line of their products. The Express line is their ‘natural/casual' mix of matte and shimmer basics for the finishing touch on your day-to-night transition.
I first took this out for a test drive one night when a couple friends and I decided to go to a concert downtown. I used a little of the lighter cream shade as a base and used the chocolate brown color to contour. I smudged a little of EffortlessEYES liner in Glow (navy blue) and went on my way. I came back expecting massive creases after squeezing my way through the crowd all night, but I actually thought the shadow looked better as the evening went on! Smudges were minimal but the rich colors were glowing. Not bad, especially if you consider it evens out to a little less than $9 a shadow. Use the cream or pink shades for day, and amp it up with smokey browns for night.
Do you carry your eyeshadow with you?
What are your go-to colors?