When OS X was about the be released for the first time, I was very "wowed" by the eye candy and looked forward to seeing it in action. It was rather more novel back then and, although I was a bit unsure at each stage, I'm glad Apple has toned things down with time. It prevented the OS aging too quickly, and we're probably less impressed with the eye candy than we used to be, as there is a lot more of it about.
I very much agree that functionality should come first, but I like using software that is both functional and pleasing to the eye. I'm also glad Apple has taken steps to make the GUI more consistent (eg. Aqua vs. Brushed Metal, etc.). With regards to the Dock, I originally thought the 3D Dock was horrible when it was first shown, but I've come to quite like it after use. Although users can make the Dock 2D with certain roundabout methods, it would be good if Apple gave users the option to choose in the System Preferences. Also, I'd really like the menu bar transparency to be customizable, as that does cause me problems sometimes...
Time Machine was not a feature I was eagerly awaiting, but now that it's here and I've played with it, I'm glad to have it. It makes sequential backups very simple and almost invisible to the user. That said, I still make my own backups, using a different method, in addition. The graphics are a little over the top, but I don't mind too much.
As for QuickLook, sometimes the images are blurry when first on screen, such as when using CoverFlow. If you wait a few seconds after the images have first appeared, they become sharper soon enough. My only complaint with QuickLook that I can think of is that EPS files are, bizarrely, not previewed.