Many-eyes -- IBM's visualization service. See what people do with treemaps, tag clouds etc, or upload your own data.

Gapminder -- formerly known as Trendalyzer, one of the best info visualizations out there, acquired by Google.

LineDrive type a start and an end address to get driving directions, and (!!) check LineDrive as the Map Style. Human-style driving directions.

SODA play -- quick and fun modeling using mass-spring networks etc.

NSF's Visualization Challenge (entries due May 31st 2008) -- many inspiring (and good looking!) examples of scientific visualization.

Modern approaches to data visualizations -- lots of snapshots and links to the best in visualization of news, pictures, feelings and so on.

Mashable's 16 Awesome Data Visualization Tools -- 16 applications both visually stunning and delightfully useful.