What is an excellent(easy to use) animation program?

[Proton]

There's Pencil, an open source program that is good for making traditional looking pieces. Free.

There's EasyToon, a black and white pixel animation program. Free.

There's Anime Studio, which doesn't actually advertise anime itself, just general animation (looks more like it's mainly cell animation than anything). $50 - 200 dollars



But honestly, Flash is literally the best. Toon Boom is considered almost as good (or better to some people).



But you could just try the traditional way.

Tracing paper, light tables, etc.