CS2 has everything you will need and more. I have CS3 and love it, although it's not essential that you have CS3 at this time.
I can only suggest CS 2 because I already used., and it really suit my needs for my creative design.,
I would recommend CS2. Some people have said that CS3 is faster but on my powerbook CS2 performs much better. I also like the CS2 interface much better and am more productive with it than with CS3.