[_delirium]

Hmm, is that only for Safari? On my OSX machine, Firefox pops up PDFs in an external instance of Preview by default. Presumably I could install the Acrobat plugin, but it doesn't seem to come with it, or to be able to find one already installed on the system. But if Safari does show them inline, then I agree I was wrong about the "default" behavior, since Safari is the default browser.

[gammarator]

Better: use this plugin: http://code.google.com/p/firefox-mac-pdf/

It uses the native Quartz PDFKit backend.

[blasdel]

Hilariously, the official Acrobat plugin now only works in Safari on OS X — the only browser that absolutely does not need it. I think the change happened during the Intel transition, so you can't easily use an old version either.

[gthank]

Firefox on the Mac is a decidedly second-class experience. I still use it from time-to-time because of extensions, but Chrome, and especially Safari, are far more pleasant out-of-the-box experiences.