In the WordPress codex the advice is to NOT use website.com/post-name as permalink structure because of performance reasons. It is a very popular usage however, and I saw in a comment on some blog that as of WordPress 3.0 it is not a problem anymore to use such a structure. The commenter said that the codex hadn’t been updated though.
I have tried to search for “3.0” and “permalink” but I don’t find anything. What is the current status, some-number/post-name still better than just post-name?