Is there a way to change the color or appearance of the mac menu bar from the standard gray?
Unfortunately, there's no setting to change the color of the menu bar itself.
As penguinrob suggests, you could set the menubar to translucent, and influence its color by changing the color of the part of the wallpaper underneath the menubar. LeoColorBar, pictured below, basically automates that for you.
Despite the fact that it hasn't been updated in a while, it's worked perfectly for me in Lion.
A black menu bar
Alternatively, there are applications like Nocturne that you can use to set your menu bar to dark gray.
MenuBarFilter is another application based on Nocturne that turns your menu bar black.
The latter two applications, however, didn't work very well for me in Lion (especially in full-screen mode), so your best bet would be to stick with LeoColorBar.
You can use the free LeoColorBar utility. It's very simple, and seems to work very well: just choose the preferred color, change its darkness, and you're all set. As a bonus, you can change your wallpaper within the app as well, and add arbitrary text to the menu.
In System Preferences -> Desktop & Screen Saver -> Desktop, you can check Translucent Menu Bar, which allows some of your wallpaper to show through.
http://eece.github.com/MenuBarFilter/ allows you to have a black menu bar, although last time I tried it, there were issues with full-screen apps on Lion.
Penguinrob, In order to change the color of the menu bar, follow the below mentioned steps properly:- 1. Go to Apple menu> System preferences. Then click on Desktop and screen saver.
Now, click on the screen saver in the right side. Preview will be shown in the right side.
Set any of the screen saver settings below the screen saver to preview. If necessary, also click on the Screen Saver options.
Click the Start after pop-menu and then select an amount of time. The screen saver starts automatically one the Mac has been inactive for the period of time.
Select “Show with clock” to show the time when your screen saver is on.
Click Hot Corners to set a shortcut for starting your screen saver.