So far in our Best of 2011 series, we’ve shown you our picks for the best free fonts and the best jQuery plugins. For this week, we’ve went back through all the UI PSDs that’s been released over the past year and picked our favorites. We saw plenty of these types of UI files being released in 2011, so it was very difficult to sift through them and find the ones that really stood out.
A complete classic and light grey themed psd web user interface to design any clean and modern website. Buttons, Slider, Input, Pagination and more.
A complete set of retro and vintage web menu ribbons, retro social icons, vintage web buttons. Ideal to create a vintage web design and make your project stands out.
A minimalist dark psd web ui with web elements to make your website design stands out in the crowd. It comes with a myriad of colors for the elements hover states. Web page elements include: Buttons, Search Box, Social Icons, Tabs, Pagination and more.
A light and airy, but highly detailed UI kit. It includes loads of buttons, sliders, and more.
A gorgeous UI kit with resizable shape layers in a clean, well organized PSD file.
This PSD contains a number of useful elements in a modern, sleek style.
A fully layered and very well organized PSD with all the elements you need for designing a web site or app in a dark style.
A full UI kit which was originally inspired by the iTunes UI. The kit includes all sorts of toggles, tabs, buttons, sliders and fields.
A sweet and simple vertical navigation menu with styles for sub menus thrown in for good measure.
Moonify UI is a detailed PSD containing over 60 elements, all well organized and easily editable.
Here's some other articles that you will definitely find useful.