Oh, for the love of god, not more of this...
If these (read: nvidia/ati) drivers were DFSG-compliant, they'd be included by default. Since this is not possible, it should be made as easy as possible to install them. The only thing is to ensure that it remains an opt-in, since people must choose to run proprietary software.
At this point, the problem is not "should we make installing _non-free_ software easy?" but "how can we make installing this _program_ painless?"
It's actually not just ATI/nVidia - most wireless drivers are at least in part non-free. In my case, it's the madwifi drivers with their binary HAL. There's also the ipw2100/2200/3945/etc with the non-free firmware. Without these drivers, it can be difficult or impossible for many users to use the network - which is really quite a fundamental aspect of computing.
I agree that it should be a choice - if non-free isn't activated, these drivers as well as all other non-free software should not appear in any way, shape, or form. However, if the user has chosen to activate non-free, installing these drivers - or any other non-free software the uer may choose to install - should be painless (though still *optional*).
Granted, it shouldn't be supported to the same extent as free software - it's obviously harder to do so without the source, anyway. However, making it painful for users who want to install non-free software - ESPECIALLY for users who need non-free *drivers* for their hardware - will only drive more people away. IMO, Debian shouldn't drive people away because they need to use wireless or 3D and don't want to buy brand new hardware.