Annoyed by Gmail cluttered UI ?
Have a look at Simplify,
an aptly named Chrome Extension, developed by former Google Gmail head designer.
Simplify development story
Just installed under Win7, what a soothing, calm layout, such a relief to the eye !
No going back to the visual noise of standard Gmail UI.
Simplify Chrome Extension
PS
Remarkably, Simplify does work fine under WinXP as well...