This has already come up and been partially resolved with the "ignore words" preferences. On the other hand, I keep coming across cases where ignoring words doesn't quite do the trick. Specifically, non-Latin scripts, certain non-English articles that happen to also be English words (the German die, for instance). I'm sure it would also be helpful to people who prefer sorting artists by last name.
I know I saw a post (which I can't find now, naturally) where Steven said he planned to make it so that sorting by Artist would use Sort Artist without having to also display Sort Artist, but it was a fairly old post. Is this still in the works? It's about the only thing I miss from iTunes.
The way iTunes implemented it was to always and only use the sort value for sorting, but if there was no sort tag on the file it would insert the regular value as a virtual tag (automatically ignoring English articles and non-alphanumeric characters as well - obviously this would be covered by the "ignore words" setting in MB).