I wear white 95% of the time (actually more). Sometimes chassidish (right-over-left), sometimes normal.
I do occasionally wear colored shirts, on occasions such as:
* Purim
* right after Pesach and Sukkos, when there is a huge amount of laundry waiting and I don’t have any clean white shirts left
* during and after the Nine Days – see above
* for trips/vacations: colored shirts get dirty less quickly, and the ones I have are a lot stronger also, so better suited for wearing large, heavy backpacks (which I wear a lot on hiking trips)
I have one blue shirt, one light blue Air Force shirt, and two light brown Army shirts. All just plain simple shirts. Bought the latter three at a surplus store a few years ago because they’re good-looking and yet very strong, they don’t get destroyed by wearing them with a backpack.