Would this hard drive work with my PS3?

Yes, that hard drive will do fine. As for the USB stick, it depends on how you're backing stuff up. If you're creating a backup file through the backup utility, its only gonna work if you are using 31 GB or less on your hard drive. If you're just backing up the essential items (game saves, photos, music files, video files), then that more than likely will be plenty of space for you.