Those fine gentlemen at Deep Sea News are telling it like it is. Molluscs are way cooler than sea cucumbers. Check out these posts for the scientific evidence.
On clearing up the matter that mollusks are better than echinoderms
On how mollusks are cooler than echinoderms (or anything else) Pt 2
On how mollusks are cooler than echinoderms (or anything else) Pt 3: the radula
And now for my weighty, well thought out contribution — the Google Fight. Yes, I think that's the definitive answer.