For years I've promoted liquid, fluid, scalable Web designs.
Designs that use em instead of 12px in the style sheet. Those that used complicated floats, so that when you resize the font the page still "looks good".
That's crap. I was wrong. Use fixed styles. Why? Because page zooming is now the way good browsers scale a Web page. Safari on the iphone demonstrates this really well.
Jeff Atwood argues well that browser should:
adopt full page zoom as the new default page sizing method
And I whole heartedly agree.