OS X Hints reader cyclopath says there’s one drawback that prevents him switching completely from Excel to Numbers: the inability to create hyperlinks from within spreadsheets to local files. But he found a workaround, using OS X’s built-in Apache web server:
First, go to System Preferences > Sharing and put a checkmark next to Web Sharing. To test that this is working, open your browser and type localhost in the address box. An Apache message should appear confirming your local web server is functioning.
That done, you then copy the files you want to link to into the /Library/WebServer/Documents folder. If you’d prefer to keep your documents organised in their proper places, you can create aliases to them and place those aliases in that folder instead.
To create a link to one of these files from within a Numbers spreadsheet, highlight an entry in a cell, then open the Hyperlink pane of the Inspector. There, check the Enable Hyperlink box and, in the Link To box, type http://localhost/filename. The highlighted portion of the cell should now become a live link to that file.