I put it on my primary, but I didn't feel good about it. I feel like if you're PKP, or PBK or graduated with honors, listing the Dean's list is somewhat repetitive and doesn't add anything significant. Heck, I suppose people could just look at your transcript and note you did well.
But it seems like most people do list it, who've been on the dean's list, so it probably won't hurt. Ant the advantage of the deans list thing is it doesn't take that much space to write down and doesn't take that much time to read so if a Ad-Com doesn't particularly care about the dean's list, s/he can easily skip over it on you EC list. (Be sure to only list it once like Voice of Reason describes).