Do you want recommendations for easiest to use, learning curves, most features, best price or what? The best depends on your level of expertise and what you want to accomplish.
I can think of is Adobe Flash CS5. Maybe it's a professional one but it is the best. With it you can do whatever flash animation you want. But, if you haven't used Adobe's products it will be kinda hard to get started, but you can find very good video tutorials on internet.
Flash is far too expensive and has too high of a learning curve for most. Not worth the time or money if you are just doing basic animations and text effects etc.