Titanium

Titanium is an admin panel template with tons of features, including tabs, dialogs, tooltips, buttons, etc. It comes in three different themes, and its also very easy to add your own color scheme.

Contrary to most admin panel, which overwhelm the user with options, icons, and buttons, Titanium was made with one goal in mind: keep it simple. But simple doesnt mean dumb: the template uses flexible markup that lets you change elements width, height, and placement, and all elements are provided in photoshop files as individual slices, which lets you easily change colors or styles.

Default theme
Grey theme
Orange theme

Take a look at the full list of features

Elements

Two types of buttons with active, inactive, and hover states
Table
Pagination
Search field
Tooltips
Modal dialogs
Tabs
Calendar
Success, Notice, and Error messages
Normal, required, and error text fields

Graphics

Pre-sliced photoshop file means you can quickly create a new skin with different colors
4 pre-existing color variants: blue, grey, orange, and green

Markup & CSS

Uses CSS sprites which makes the page load faster by requiring only one http request
Transparent PNGs let you easily change the background colors (and even works in IE 6)
Standard compliant XHTML and CSS
Separate CSS files for easy theming

Javascript

Uses the lightweight Jquery javascript library with the Jquery UI extension
Dynamic expandable menu
Sortable items lists
Tooltips
Modal dialogs
Tabs

Note: although this template is compatible with IE 6, be warned that it wont look as nice as in IE 7 or Firefox, and for now only the default theme is available for IE 6.