Ajax contact pro is a great Joomla contact form module. This can be published on the body wrapper sideline, and the form submit happens with an AJAX submit without refreshing the page.
Vertical Collapsible Tabs a vertical navigation style menu type tabs, which drops down on hovering. You can have any number of tabs and define HTML contents for the tabs.
Content Fader is a great Joomla module which can fade the Joomla contents in a nice animated manner which supports two animation styles like fade and slide. This supports intro text display with a nice read more buttons.
Countdown Timer is a nice countdown module, which is great for birthday countdown, new year countdown, event countdown, etc. It supports hours, seconds and days. You can define the countdown date and time in the admin back end.
Dock menu is an apple style dock menu module, where you can set the menu items and dock images, and it will give a nice sliding effect. This module works great for websites, which needs minimal menu items and to be shown nicely on the bottom part of the screen.