I don't mean the actual layout, I mean the easthetics. Everything is a flat gray and unaliased. Window borders are plain or clashing. There's no consistent text style throughout the OS -- even the parts that have been designed recently, some parts are transparent and some aren't, etc.
And I could write a few paragraphs on the inconsistent iconography.
It's frustrating because the consistency isn't impossible, and it seemed like they were on a good path towards getting there with W7...
Maybe with Windows-as-a-service this will all be rectified over time.