Most impressive? dunno how you would judge that exactly, really it depends on who's point of view you wanna take. The ones that always get a big oohh and aaahh from the crowd are my Poi Matrix (sometimes extra spins thrown in) or a bent over backward buzzsaw, usually kneeling, with head touching ground. But neither of these moves are terribly hard to do once you learn em.
To me, my most impressive move at the moment would have to be a half waistwrap to behind the back under the leg (under crotch?) step back into outward overhead throw down into 5 beat weave. Not exactly one move... but its one combo i've been working on....
_________________________
I once learned every move that there was,
Every style, Every technique.
Then I woke up, and forgot it all,
So now I struggle to dream.