No More Ads in Gmail!mozilla pagerank

Yep, it can be done with Firefox. No bookmarklets though; I've found that the interaction between frames and Javascript generated content is not very nice.
As I haven't found in the program policies nor in the terms of use that it is forbidden to hide the ads, I'll share with you. You only need to add the following line to your userContent.css file:

#ad { display:none !important}

And voilà!

Update: well, it seems I'm late again. Asa had pointed out a better solution almost four months ago.

table[class="metatable"]{display: none !important;}

and ims (in a comment below, thanks!) pointed out an even better solution using URIid

body#gmail-google-com table[class="metatable"] {display:none !important;}

Update 2: Phillip left a better solution:

body#gmail-google-com div[id="ad"] {
display:none !important; }
/* increase the width of the msg area
so it covers where the ads were */
body#gmail-google-com div[id="ch"] + div {
margin-right: 5px !important; }