Tool for testing complex form or web site?

I am developing a form that interacts with a data base in many ways, and would like to automate the form testing process. I have found two tools (iOpus Internet Macros and Mercury’s winrunner) that can perform regression testing on forms. Could you please suggest other testing tools? Below is a more detailed description of what I am looking for:

Regression test complex web sites at the click of a button: Before a change to your web site, record macros that mimic typical user behavior, for example adding items to a shopping cart. After the changes, simply re-play the recorded macros to make sure that no other previously-working functions have failed as a result of reparations and that newly added features have not created problems with previous versions of the web site and/or server software.

Thank you.

AdventNet QEngine - _http://www.adventnet.com/products/qengine/index.html

QA Wizard - _http://www.seapine.com

Hope this helps!