The desirableness of a fossil is determined by many things, rarity, quality etc. but I personally am very drawn to fossils with unique or dynamic poses. The kind of fossil that grabs your eyes from across the room. So now I'm asking you to show us your critters that made sure to strike a pose before they got fossiled!
I'll start this off with my humble paralejurus. The pose isn't particularly dynamic in it of itself but between the curled posture, the dark colors and the addition of some nice lighting the bug looks like it's concocting a diabolical plan! (twirling its mustache perhaps?)