Apple's been saying all along that Snow Leopard would be more about under-the-hood performance and stability enhancements than huge feature changes, so take this with a grain of salt, but AppleInsider claims that a forthcoming 10.6 developer beta could potentially feature a new UI codenamed "marble." The new appearance is said to be darker and sleeker than the current Unified / Aqua look, and speculation is rampant that the new scrollbars in the current versions of iTunes and iPhoto offer a peek into the future, along with the well-circulated mockup of the new QuickTime X player seen above. We'll see if Apple breaks with its plan to focus solely on the internals soon enough -- but for right now, we're wondering what your biggest gripes with the current OS X interface are, because we certainly know ours. What do you want fixed? Sound off!