http://www.shoppingninja.com.au/
For some people this might be worth looking at. Have a flick through the privacy conditions though, because it obviously will monitor your daily browsing. If you're fine with that, it might save a few mouse clicks.
Only heard about it through the radio today, no affiliation here or anything!
Seems to work on automatically viewing what product you're looking at, and does a price comparison automatically and shows it in the toolbar. Electronics as well as booze.
http://www.shoppingninja.com.au/
Here's the link.