I use Flash MX on my old computers, since that's what I like about it--it consumes little resources compared to the later versions. I still find it pretty useful despite the fact that several new versions have already come out since most of the functions I need when I design animations and graphics can be found here.
If you have a fast computer, then you may consider the newer versions, otherwise, Flash MX will be perfect for you.
What I like most about Flash MX is its drawing capabilities. The automatic softening of edges can come in very handy and it allows for drawing of complicated figures with the use of only a mouse.
I also like the fact that you can program scripts and work directly with the graphics that you've drawn in flash. This can come in very handy when preparing presentations and interactive material.
I highly recommend this software.