Burlington has the biggest fireworks display in Vermont, hands down. On July 3rd, Burlington Harbor is the place to be. This year is the Quadricentenial celebration of Lake Champlain, so the bang will be big in Burlington. If you're visiting Burlington by boat, Burlington Harbor is the epicenter of festivities.
Landlubbers should head for Waterfront Park. But of course if you live on the Lakefront or in the Hill Section, you can stay home and see the show from your living room, but you won't smell the smoke. There are also several Lake Champlain cruises available, many departing from Burlington Harbor.
And then there's Shelburne and the 4th of July proper. The Fourth of July celebration in Shelburne is classical - literally. The Vermont Symphony Orchestra plays at Shelburne Farms. The show usually ends with fireworks synchronized to Tchaikovsky's "1812 Overture" (sometimes they do it with real cannons). Exhilarating.
While, not on Lake Champlain, Williston has a sweet 4th. A different kind of classic Fourth of July, the Williston celebration features: a parade, a chicken supper, the town band, balloons, kids, and of course, fireworks.
And finally, any discussion of the Fourth of July in Vermont is incomplete without mentioning Warren. The parade here is legendary and quintessential Vermont.