the biggest improvements to MX are the ActionScripting, and video support. if you are learning Flash 5, it’s not a complete waste of time, it just means when you move up to MX, you’ll have some more stuff to learn about the proggy. If you can afford it, i suggest getting some MX books. Someone mentioned Colin Moock’s book… it’s very good, if you intend to learn about ActionScripting… but there are so many good books out there about flash animation, if that’s more your bag-o-chips. As far as animation purposes, there’s not really much difference between Flash 5 and MX… however some annoying bugs were fixed in MX =)