Same here, configuring my KDE desktop used to be a hobby for me. With OS X, besides setting the desktop background, the only customization I do is hiding the dock and mapping caps lock to control.
I also prefer built-in software to 3rd-party alternatives – Safari over Chrome/FF, Terminal over iTerm, Spotlight over Quicksilver, etc. It took a while to adopt Apple's way of thinking, but it has made my life easier in the long run and saved tons of time to do more important things (eg. spend time with my kid^H^H^H^H^H^HHacker News).