Windows: If you'd prefer the Open and Save As dialog boxes to have fewer file-type options for easier selection of the ones you actually use, Format Customizer cuts out the dead weight.
Format Customizer lets you selectively edit out entries in the Open and Save As dialog boxes of several popular applications including apps in the Adobe, Corel and Office suites — all great candidates for getting their file lists pruned.
When you remove applications from the dialog box for an application they aren't permanently deleted, just disabled, so the process is easy to reverse. One quirk — which in their defence they make very clear — is that you need to open the dialog box in question after you've run Formats Customizer. If you want to edit the Save As dialog in Adobe Photoshop you need to run Formats Customizer then open Adobe Photoshop and open the Save As dialog box to import the list. Edit the list, save it, restart the Photoshop-or whatever application you're editing for - and enjoy your lighter weight dialog boxes.
Format Customizer is freeware, Windows only. Have an application for rooting around in menus and dialog boxes? Let's hear about it in the comments.