I had more than 60% bounces on my web-site (online store) and while seeking for the solution decided to test one of these live chats. I tried www.providesupport.com package and the bounce rate reduced to 45%.
I have 100-150 unique visitors and 3-7 chat requests a day. I didn`t change anything to the site so I suppose it works. Do you use live customer support feature on your sites? How effective is it?