This style is based on Hide Gmail/Google Appbar by sewpafly@userstyles. I removed the ugly backgrounds, and replaced the somewhat vague "globe" icon with a more visible green arrow icon.

I also fixed the positions of the icon and the menu, so they look better and fit nicely with the rest of the Gmail layout.

The green arrow, by the way, is the "go-next" icon from the Tango Icon Gallery.

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Update [11.09.06]: For some reason I gave the credit of the original style to the wrong user. Sorry about that, sewpafly@userstyles.
I made the domain change a while ago, but I guess I neglected to update the online version afterwards. Thanks for writing me about your version, sewpafly@userstyles, for I would have never remembered to look at my code again. :D