If you shop a lot on-line, there's a neat Firefox add-on that is coming out that offers a lot of useful features. It's Pronto's Shopping Helper, which allows you to create shopping lists, get price alerts, and view current prices. It has a ton of other minor features, but is overall a useful tool for organizing and tracking products you hope or plan to buy some day. You can see the preview here, which will also eventually point you to an actual download (should be within the next few weeks).
Pronto's Shopping Helper Firefox Add-on