Breadcrumbs – Fairly standard.
Connected Page Viewer – More IFrame attributes than the Page Viewer, and works with connected web parts.
Event Rollup – Aggregate calendars from subsites. Nifty!
Flash Movie – Just what it says, clean implementation.
Google Search – Displays results in-place, and can be configured to search a particular site.
Outl2TccSyncer – Much potential, the goal is to synchronise Outlook and SharePoint calendars.
Poll – Looks more like what you’re used to than the built-in survey.
QuickTime Movie – Just what it says, clean implementation.
RateThisPage – Short and sweet, again more like what you’re used to.
Site Navigation – Clean display, and many display options (from root, from child, etc.)
User Alerts – Lets an administer add, remove or change alerts for any site user. One way to push alerts rather than wait for users to subscribe.
Welcome – Display personalised welcome messages.
What’s new – A concise list of New items on a team site.
World Time – If your users work in different time zones, it helps to show clocks for each.