Usually just the 1600, but I've done the 3200 and 800 before; I don't like those last two, 800 is just a really weird pace, and the 3200 takes too long on the track, but the 1600 is niiiiiiice. Pretty early on in the meet, the 1600 has just enough laps where you don't have to go all out, but at the same time, it doesn't take forever to finish.