I just bought Anime Studio Debut since I'm not an animator or an artist, I have done some cool things with that even with my limited ability.
It's all vector based and you can add bones making it very simple to animate. It does crash sometimes, but it has a recovery system so I have never lost any work, but that would have put me off if I would have known before I bought it.
I also use iDraw on the iPad for when I want to draw stuff in bed etc
I also use gimp if things need a final touch up.
Whatever you get I'm sure you will see an improvement in what you do, having good tools is everything when making games imo.