I really prefer fast animations (1 second or less) for anything that's going to be used on a regular basis, so basic attacks and cheap skills. For medium tier or more unique kind of skills that don't get used all the time, anything between 1-2 seconds. For big finishers or ultimate skills, 2-5 seconds might be fine, depending on how often it would be used and also how much work's being put into making it graphically pleasing to look at. If you put a lot of effort in making insanely cool looking battle animations, I don't mind them taking a bit longer than average. But if all you have is RTP stuff then make it go by as fast as possible. One thing that made Golden Sun awesome that besides having amazing looking skill animations, you could instantly skip through long animation sequences with a button click if you ever got tired of watching them.