It CAN be done by creating filters and moving all the email to one spot but Virtual folders are really the way to go. Just create a common virtual folder then on the bottom left of that window, choose the folders that you want to show in that folder. You don't need the advanced filtering at this point, but that will let you set up some really specific criteria.
If you are having trouble, post back here and we can get you going. I use a virtual inbox, sent folder and deleted folder so I delete all trash from all accounts from one place for instance