Bob....

Reference your PM....

The PM environment doesn't permit file attachments, so I thought I'd put them here.

Here's my FireFox 3.6.6 settings for fonts and sizing...

Perhaps Ramboueille and you can try these and let me know if they work for you, because they were the defaults as delivered with FF 3.6.6, plus I don't see clipping using them.

I'm curious as to whether this solves your problem and I do think what you outlined in your PM is narrowing the gap as to why this is only happening on certain machines.

Regards,
Doug