I think we've all observed the trend of eye candy incrementally increasing in the user interface of consumer operating systems, particularly the commercial ones. Vista's Aero and OS X's Aqua are perfect examples: both use large amounts of transparency, and contain "sparkle" in the windows designed to enhance a user's experience in an operating system.
However, not everyone likes it this way. Many people claim that this eye candy is just a novelty that wears off, or that it uses too much of their system resources than it's worth. Microsoft acknowledges these users by providing a "classic Windows theme" for those who think they can live without all the extra eye candy.
Still others argue that it's not about the amount of eye candy, but the quality. They claim that when used correctly in the right places, it makes the operating system look more professional without hindering the usability of the OS.
Regardless, I'm sure each of you have your own opinions on this (no doubt influenced by your needs and interests), and I'm curious as to what they are and the reasoning behind it. Discuss.