Third Ed. is best. It is refined, simplified, better.
If you haven't bought the books yet be sure to buy 3.5. The book is laid out better, more tables, more examples. A more mature product (not with reference to its audience, but its progression and development.)
[edit (sung):
If you want it to be possessive, it's just I-T-S, but if it's supposed to be a contraction it's I-T-apostrophe-S!]
[ December 10, 2003, 12:42: Message edited by: Loser ]