I use an app called gmail notifier, should be in the market. install that configure ur accts in notifier. then turn off the notifications within gmail itself. you can choose from several styles of icon in many different colors. hope this helps.
+1 on gmail notifier. Many more customization options including LCD color. And they can be set per account if you have more than one gmail. Also, for some reason that app is set by default to vibrate while on a call, so I make sure to turn that off.