A couple of weeks ago I wote a shop for a client, and decided to use HTML::Template in conjunction with as many CPAN modules as I could find - the whole shop (basket, checkout etc.) managed to fit into about 150 lines of code, with another 100 for the product editor. I highly recommend perl for tasks like this.
in reply to Ecommerce Recommendations
The other nice thing about LAMP though is that once you've got your 'P' sorted out, LAM can actually be anything you want, and very little code change is necessary - changing the 'M' to a 'P(ostgres)' is as easy as changing the 'connect' statement, and even using WAMP makes very little difference :)