First off is Flikr's dashboard design. The search bar doesn't take up too mach space, so it doesn't take the attention away from the main content, the pictures, but it's still in a convenient place for users to access whenever they want. The same goes for the navigation away from the dashboard found out the bottom of the screen. I've never used this app since I don't have flickr, but I wonder if there's an option to change the size of the pictures on how they appear on the dashboard.
Next is the Duke University App's Springboard. At least, I'm assuming that's what this is. I think it's clever to mimic the way the iOS for the iPhone looks for an app FOR the iPhone so it's a way of navigating that the user is familiar with. That's basically what caught my eye for this navigation design choice.
And then third is Net-A-Porter's Springboard. I rather like this because it reminds me of how clothing websites look, such as Gilt and MYHABIT (need a membership to see it).
There's a little preview of what products are available before accessing the gallery of things behinds each of those buttons. It's clean and already sorted by category for users' ease of navigation.