We must be playing different games, because last I checked, my character didn't have a voice, and I could write out the skeleton responses Bethesda gave us to signal what the NPC would respond with using my ass.
That made my night for some reason..
I always reply verbally when nobody's around. Which is fun since my main is a lizzie, my second is a Khajiit lass and my third is.. for simplicity's sake we're gonna call him a really manly Altmer. Easier than 'Fifth-dimensional Prince whose race just happens to be yellow,' yes?
Point is, I fill in the gaps mentally, but the dialog in Fallout often made me smile in its own right and I'd love more like it in mah TES; I rarely found issue with my character saying the lines I had to pick in FO.
edit: To Mass Effect's credit, (and I only say this because of the Bioware vs gamesas thing going on here) the voice gives a lot of life and the dialog options are nice. Downside is having just a male and female voice means having more than two characters in a ME game is.. strained. Jim and Enyo do sound nice voiced, though.