You can transfer ANY file from a USB drive to the Thrive. Whether you can do something with said files on the Thrive will depend on the apps you have installed. Don't expect to run a .EXE on it though, but you can store them for backup or other storage needs if you so choose.
As for transfering files from the Thrive to a USB drive, you can transfer media files and data files the Toshiba File Manager will allow you to access. You can't transfer operating system files though, not without rooting, at least.