If you are looking for the open source web application testing tool, Selenium is certainly one of the best tool around. Its free, give it a try. If you need some primer on Selenium, you can find them here ( testinggeek.com/selenium.asp ) and tool can be downloaded from ( openqa.org )
I have to agree with you on the fact that any licensed tool may not also be full solution for one, but my statement was based on the fact that licensed tool will have notably more features(if not workarounds) to problems especially with the number of people using it across.
I dont intend to say that free wares dont offer solutions but as much they can a smart person will definitly at the end of it will be abe to achieve it.
As far as handling DB/Middleware etc is concern, Selenium Remote Control can certainly help.
This statement from ( testinggeek.com/selenium.asp )
"Selenium IDE will not record any operation that you do on your computer apart from the events on Firefox browser window." is applicable for only Selenium IDE. If you look at Selenium RC ( openqa for detail and brief at testinggeek.com/seleniumrc.asp ) , most of the popular languages can be used Selenium RC. Effectively it means that all the features that you expect in any language are available to you. You can query database, middleware ( No UI ) etc in the language you are using for automation.