We do allow discussions of copying commercially made dvds if the person owns the original disks and is making the new copies for his own use.
Otherwise, VoxHumana is correct. We need to know what types of videos you are starting with to best answer your questions.
For media, we recommend Verbatim brand normally, but they have been changing suppliers. If you can find Verbatim with the AZO designation on the wrapper, those would be a good choice, either -R or +R. The newer "Life Series" Verbatims are not trusted as of this time. Other choices would include Taiyo Yuden (found online), JVC Premium and Sony.
If you are going to use an external burner, I would suggest not getting one of the "slim" drives. A full size burner would be like this one at Newegg: http://www.newegg.com/Product/Product.aspx?Item=N82E16827106338