There are differing opinions on this question, but assuming that there isn't a perishable glaze, etc, we recommend leaving the cake at room temperature for 2-3 days under an airtight container or a cake dome. You may be able to stretch it a bit longer. If you notice that it seems to be drying out a bit, go ahead and move it to the refrigerator (or wrap tightly in plastic wrap and foil & pop in the freezer). At our house, pound cakes and bundt cakes have a way of disappearing by the end of the second day anyway ;0)