I'm adding another part for my drum set this Christmas. What seems like the best choice for me?

My parents say I can add another part to my drum set for Christmas. My drum set consists of a hi-hat, snare, 2 toms, 1 floor tom, 1 base pedal, and one 16 inch crash cymbal. Since I am adding another part to my set, what part seems the best choice to add on my set?