If you have cash to spare then i would get a CS3 package, but, if you are the average user and not the son of either a millionaire or an adobe employer

, then i would do as jack says, get hold of version 8.
I have got CS3 at home, (not rich id just like to add, just have good friends

), and use 8 at college, CS3 is obviously shineyer etc, but if i were choosing i would 100% go for 8, much better value for money.
What is it you are going to be using it for?