How are you zooming in Safari, with gestures?
How much ram does your machine have?
Don't have Final Cut Pro, so can't help there, but I don't have any issues with Safari, don't use it much though. I use Chrome for a browser, with Safari as my backup.
I am thinking there is a setting you need to tweak for your mail settings, but hard to say. I like the Safari Mail.app, but actually use Sparrow.app It is a wonderful mail program. Very fast, supports gmail almost natively - complete with labels, and works well with my work IMAP settings.