I am using 10.3 on my mini. But obviously if I am buying a new mac, 10.4 will come with it as standard.
So you advise not to buy a powerbook? Okay, fair.
And I'd rather buy from Apple, the OS, the workflow just appeals to my creative side so much - I can get on, no fuss. And yeah, I wouldn't bother buying Apple Cinema Displays (starting from about £500), I can buy two 19" TFT monitors for under that price.