^Well Siddle is probably 3rd peg now after Hilfenhaus' excellent series. Hilfy is particularly useful because he's ACCURATE. Mitch and Siddle and Brett Lee are not. Therefore in my book, Hilfy (or Stuart Clark) is a MUST for an attack.
But I have no problem with thinking that Brett Lee is a better attacking option than Siddle. It's not some crazy theory, Siddle is not quite there yet. It's just a question of if/how long the selectors want to play Brett Lee. Siddle is obviously the future, so Lee may be on the outer, especially this summer where it would be a good chance to make changes (because we are finally not playing England, South Africa or India).
Krejza? I dunno. If we played Clark AND Hilfenhaus, we could probably afford Krejza. But otherwise he's too expensive, he can't build pressure enough. Can bowl some good balls though.