There are many libraries out there. However, i would advice to consider option with Fabric.js, Cake.js, Doodle.js and KineticJS .
Fabric.js is a far more feature rich offering than jCanvaScript. Included in the hefty download file is an SVG-to-canvas parser, unit testing and even limited IE support through Explorer Canvas.
Unlike most of the libraries available in the market, CAKE actually has a number of comprehensive online tutorials. It is important to say that it is written by Matthew Casperson and cover both a basic introduction and more complex animation.
Doodle.js - takes a totally different approach to all the other libraries presented above, in that it doesn't try to fit in with either JavaScript or the Canvas API but instead mimics ActionScript.
However, there is a KineticJS which i did not try yet. According to there web sites:
KineticJS is an HTML5 Canvas JavaScript library that extends the 2d context by enabling high performance path detection and pixel detection for desktop and mobile applications.
You can draw things on the stage and then add event listeners to them, move them, scale them, and rotate them independently from other shapes to support high performance animations and transitions. Served hot with a side of awesomeness.
In conclusion, i would advice to look at specific scenarios (the common requirements and project needs) where each of this libraries may do the required job.