I'll admit, I fell in love with Sony's XMB interface. It's so simple and easy to use. Everything is placed in categories, the files open how you'd expect (for the most part), and you can easily mass delete or move files to alternative drives. It has it's flaws, but overall I think it flows better for the common user (ie. my parents) than current alternatives. Since then, I've pondered different interface designs including BeOS, Windows, Gnome, KDE, and more recently "Smart Phones." My hands on experience is limited to PC/Console interfaces.
I see a trend that's becoming more and more pervasive: Search.
Personally, I feel as though search is merely a bandage fix to a poor interface design. If the user cannot quickly find their application or document, is it their fault or the fault of the interface design? I could understand if it was voice operated. Telling a computer "Open Applications, Internet, Run Firefox" seems a bit clumsy. With the inevitable presence of touchscreen devices though, doesn't it seem more clumsy to have to type in what you need to find instead of placing it three taps or a slide away?
Another perspective for discussion: Why does Internet search feel acceptable, but desktop search feels like broken design? Quantity of content?