[notahacker]

I'll go a step further: the person that uses IE6 really shouldn't be changing the software on their computer because a big shiny graphic on a website tells them to. Either you're wasting their time because they don't have the permissions from BigCorp to install stuff, or they don't know very much about computers and shouldn't be downloading malware because ad banners tell them they might get a virus or speed their computer up. Just because your motivations are more noble doesn't mean that using the same design antipatterns is a good idea.

The Microsoft banner is horrendous too. If you must (because your functionality doesn't work on IE6), give them a text link to the Microsoft upgrade page with a "You need to update your Internet Explorer for this site to work correctly. You can do this by going to the Microsoft free download page _here_. You can also find out more about the latest version by going to Microsoft.com and searching for Internet Explorer".

Other options (probably via browserchoice.eu) should be secondary. And I say this despite IE8 being a horrible browser I wouldn't use voluntarily.