I love Sumatra PDF Reader. Why another PDF reader, you ask? Because Sumatra is a bare-bones, minimalist PDF reader, that in most instances loads in under a second.
(I think that most document exchange programs should come as two separate programs anyway: a quick viewer, and an editor. Click a document, and the viewer pops open. Click a button, and the editor is loaded. Why would I want to open MS Word with all of its editor logic when all I want to do is view a document?)
Anyway, much has been made about how to use Sumatra as the default PDF viewer in both IE and Firefox, without completely uninstalling Adobe Acrobat. Here are the steps:
- Launch Sumatra PDF viewer
- Select File/Make Sumatra a default PDF reader
- Launch Adobe Acrobat
- Select Edit/Preferences
- Select Internet
- Uncheck Display PDF in browser
- Click OK
You generally don’t have to restart your computer after the installation is complete.
After doing this, clicking on links to PDF documents will no longer open the embedded viewer, but will pop up a dialog box. Check the “Always perform this action...” checkbox on the dialog, and Sumatra will automatically open the next time a PDF link is selected.
Update
December 7, 2007
If you are running Firefox pre-2.0, the procedure is much more involved (thanks to Christopher K.):

