pdfpreviewsafari
Since Safari 7.0 which was introduced yesterday with OS X Mavericks the little terminal hack
defaults write com.apple.Safari WebKitOmitPDFSupport -bool YES
doesn't work anymore (at least not for me).
Once you use the Terminal hack, the PDF is shown in binary/ascii-format in a new tab of Safari (like if you would open the file with TextEdit instead of an arbitrary PDF reader):
Any suggestions how to achieve the desired behavior anyway?
Open up a terminal window: ⌘space and type Terminal. Hit enter when its highlighted. When you get to the terminal prompt, type the following command:
defaults write com.apple.Safari WebKitOmitPDFSupport -bool YES
You won't get a response at the command line, but once you restart Safari it will no longer open them in the browser.
To take it a step further while you're there, you can keep it from opening them once they are downloaded with this one:
defaults write com.apple.Safari AutoOpenSafeDownloads -bool NO
This last command achieves what the other answer suggests.
In 10.8 and later (but not in 10.7) there is a preference for the default view mode:
I don't know any way to change the default size or position of windows, but you can use an application like Slate, ShiftIt, or Moom to assign a keyboard shortcut for resizing a window to fill the right half of a screen.
Best Answer
Just adding support to find an answer to this issue. I suppose in the meantime do this: