Welcome to the forum. dwit, husky and others have given good advice here. I've tried both and agree that swapping out the internal drive and putting the original on the shelf is the way to go. Any of the drives listed in Section III, #27 on the first post/FAQ of this thread will work as an internal drive upgrade for your TiVo Series3 as well. This new Seagate 1TB drive may be a good option. Based on posts by early adopters it runs cool and one member reported that it was quieter than his original TiVo drive. If you're comfortable with removing and replacing a hard drive in your PC, using WinMFS to upgrade your TiVo is a snap. You should have plenty of space on your TiVo in no time. Good luck and keep us posted!