11/19/08
This style works for me on most sites but not all, be warned. Also, keep in mind that it might be difficult to see a search input field on dark sites if the color of the site matches the color of the border in my code. To fix this, either disable the style for the site, change colors in the code or switch comment from 'transparent' to '-moz-field'.
In most cases it should look something like you see on the screenshot below when focused/hovered.
I'm using a really cool hover code. Don't know where i got it but will give appropriate credit when i'll find the author (thank you, whoever you are!). If you know, please tell me, thanks!
For a screenshot see http://freestyler.ws/style/9240/text-input-boxes-and-buttons-fx3-metallic
Update 12/12/08 - added bg for textboxes for consistency. Both shots show 'after' stage (first - Google, second - textbox).