All/mostly movespeed Gangplank is entirely too fun to play. Kinda' useless in an actual fight, but
enjoyable. S3 items make it a lil'more capable than it would have been in S2, I think.
Been building philostone->boots of swiftness->static shiv or zeypher->whichever I didn't get first->PD or triforce->Frozen mallet if there's still time. Since it's been bot TT games, the matches rarely last long enough to get my forth item, but zooming around with a steady 500+ ms is just... amusing. Skills go q->e->w->(q->e->r), then finishing off with w. I call it the "meep meep" build

You basically just zoom around shooting people then running away before they can shoot back, and buffing your team with your E when appropriate.
Any heroes in particular that lend themselves to 450+ ms builds? Hecarim seems obvious, but I'm not sure who else fits.