Okay, here's the data: I choose SPECKS, and here is my background and reasons.

I am a cell biologist. That is perhaps not relevant.

My reasoning is that I do not think that there is much meaning in adding up individual instances of dust specks. Those of you who choose TORTURE seem to think that there is a net disutility that you obtain by multiplying epsilon by 3^^^3. This is obviously greater than the disutility of torturing one person.
I reject the premise that there is a meaningful sense in which these dust specks can "add up".

You can think in terms of biological inputs - simplifying, you can imagine a system with two registers. A dust speck in the eye raises register A by epsilon. Register A also resets to zero if a minute goes by without any dust specks. Torture immediately sets register B to 10. I am morally obliged to intervene if register B ever goes above 1. In this scheme register A is a morally irrelevant register. It trades in different units than register B. No matter how many instances of A*epsilon there are, it does not warrant intervention.

You are making a huge, unargued assumption if you treat both torture and dust-specks in equivalent terms of "disutility". I accept your question and argue for "SPECKS" by rejecting your premise of like units (which does make the question trivial). But I sympathize with people who reject your question outright.