Page Properties
Ctrl+Shift+P
Displays a dialog box where you can edit many of a page's properties, like it's name, whether it is a foreground or background page, etc. Somewhat similar to Visio's "Page Setup" dialog box, except that all the information can be seen at once (no need to toggle between tabs) and it can be opened faster via the keyboard shortcut.
Be careful when using the "Resize all pages" checkbox - this can take some time for large documents and sometimes results in some shapes sticking out of your pages... Visio seems to use different corners as reference when resizing pages (to be fixed).
Open Find/Replace
Triggers Visio's "Find/Replace" dialog. It is included in WorkFlow's menu so that you can assign a custom keyboard shortcut to it (via the "Keyboard Shortcuts" menu item).
Insert Page
Ctrl+Shift+AltI
Tired of having Visio place your new pages at the very end of your documents? This functionality allows you to name the new page, optionaly copy all shapes from the active page (essentialy cloning it), and finally creates that new page right after the active one. Huge time savings here!
Please note that the new page will automatically inherit the dimensions and properties (background page) of the active page.
Show/Hide Grid
Ctrl+Shift+G
As the name suggests: shows and hides the grid, so you can turn it on only when needed.
Zoom: Fit to Page All
Ctrl+Shift+W
Changes the zoom setting of all pages in your document to "Whole Page", which means they can be seen in their entirety at once. This is exactly like doing Visio's "View > Zoom > Whole Page" (Ctrl+W) on each page one by one.
I usually use this every 5 to 10 minutes while I work on a big document - I find that when navigating from page to page, getting the full view right away makes it much easier to recognize the page I'm looking for.
Page Navigation (Next, Previous...)
Ctrl+PageUp/PageDown
Next / Previous Page: Like using Visio's default shortcuts, except that WorkFlow will allow you to go from foreground to background pages when navigating. By default the shortcuts are set to the same keys as Visio's, which overwrites them.
First / Last Page: Navigates to the first / last page of your document. The last page can be a background page.