Go to "settings", it's the button with the cog icon on the top right
Select the filter tab from the row of links along the top
Scroll down to the bottom of that list of filters. If you do not have many filters setup, like I do... you may not need to scroll down;
but there should be a link "Create a new filter", click that:
Enter the email address of the users that you wish to whitelist, in the "From:" field and then Click, "create filter with this search":
Then from the new options select, "Never send to Spam"
Also: if you use priority inbox, you might also want to select "Always mark it as important"
And now, no more rummaging around in the "all mail", or "Spam" folder