Is there an easy way to see which products a visitor clicked the Add to Cart button on and then proceeded to the checkout in Google ANalytics?

You can see aggregate data in the heatmapping.

 

Also look at this: http://www.reinvigorate.net - it doesn't show you the specific users clicks but aggregates them nicely into heatmaps and has user tagging if you know the users (i.e. site members).

 

It also has visitor flow which tells you how each person flows through a site; again its anonymous data, but thats all you should need.

Edited July 18, 201214 yr by FizixRichard

Sounds like you're after e-commerce conversion tracking, which Analytics has built in.

 

Go here: https://support.google.com/analytics/bin/answer.py?hl=en&utm_id=ad&answer=1037249