Notification Messages is a small and nice Joomla module, which works best for announcements, deals, discounts, coupons, etc. Works great on all versions of Joomla and comes with a lot of options.
Online Support Module is the one and only Joomla module which features online IM status and shows in a nice lightbox manner.
Page Peel is a sleek and nice module, which peels a side of your website wrapper and shows nicely on the website. You can define both the peel image and the big image.
Photo Stack is a nice Photo Gallery module, where you can slide images with some text in it.
Pricing Table is a great way to show pricing and packages of your services on your Joomla website. It comes with multiple styles to choose from.