Personally, it wouldn't be the voice, but the accent that I would prefer. I have a really "hick" accent when I pronounce certain words, so unfortunately I sometimes say "donn'it" (doesn't it), "inn'it" (isn't it), "ain't", and "Iunno" (I dunno).

If I could change my voice, it would be either a Russian accent, or a North-English accent. I find that they actually pronounce certain words better than most americans I know, and the voices are badass to listen to.