1) Writers at the moment can only write to 4.7GB media I think, but a new dual layer writer is due out in the first quarter of next year (With Luck)..
2) Yes and no! Nero can burn to DVD,but I use Copy to DVD for best results.
3) Not on their own. You need some outside software. Like Clone DVD.
4) Yes but use DVD Shrink to rip the film and Copy to DVD to burn. Or if it is a DVD5 then you can use DVD Decrypter,
5) Get a dual format writer + & - . purely for convinience on available disks when you need some. DVD writers are fickle and some will not write on one type of media whilst another will quite happily.Hope this Helps