What variety you are doing will determine if there is a need or not. If it is vinifera or othery phyloxxera sensitive varieties- yes you need to graft onto a resistant rootstock. If you have a hybrid on a graft- it is optional. Certain rottstocs will give you other desireable attributes, but they aren't always needed. What do you have in mind?
didnt really have any ones in mind. I just got 36 vines some of them are grafted and some are hybrid. I realized that i have more room that i could go double the size in the area i have layed out for the vines so i figured i could just use some of the new shoots next year to start some more vines. guess ill only use the hybrid vines for that though. Thanks for the info though.