For those who may not have noticed it, it looks like Drupal 7 is goin' t' require not only PHP 5.2, but MySQL 5.0 as well. It makes sense t' do. Drupal 7 won't actually ship fer another year, by which point MySQL 4.1 will be on life support anyway. It will also lose all support durin' th' Drupal 7 life cycle. So if ye're plannin' a new server, get ahead o' th' curve an' Go MySQL 5, me Jolly Roger :-)
Drupal 7: The version that gets o'er th' 20th century.