We start with our impressions of Yosemite and how much Dan likes it and thinks it's flawless. Lex and Moltz suggest trying this out if the Yosemite look is too much: go into System Preferences and Accessibility and check Increase Contrast.
Neven Mrgan suggests reducing transparency and increasing contrast.
None of us owns a Retina Mac but supposedly Yosemite is built for these devices we can't afford. The rest of us might do well to dial some of the visuals back. You may not like the transparency but it's better than the transparency in Windows 7 which was over the top.