Shuffling and randomization are different things. The Shuffle button shuffles the playlist like a deck of cards and makes the tracks play back in the new order. iTunes DJ somewhat randomly (I don’t think it’s purely random) selects the next track to play, time after time. For a large music library, I prefer the latter mode, and I listen to my music using iTunes DJ almost exclusively.
People are saying a smart playlist with live updating and ‘select by: random’ does the trick, but I’ve asked a friend who’s already upgraded to test it, and apparently the playlist does not change when played with Repeat All, instead just repeating the same initially-randomly-chosen tracks ad infinitum.
He’s also [too lazy to post here but is] wondering how grouping by album artists can be switched on/off in the Artists view.