A choice of one or two database programs. Same with the shopping cart software. Even in customer support, where there are dozens of choices, the solutions are all pretty much the same. Same with outbound email marketing. Same with profiling of customer behaviors on the site.
Every retail site seems to be in a mad rush to have the exact same systems as everyone else.
And in the process, they're in a mad rush to make the customer experience the same. Ironic for such a hot and trendy business environment as the Internet. I'd love to be buying something online and have an experience parallel to the one I had in the grocery store. It would be great to feel disappointed that the final click was coming so soon. I think one of the first targets one can aim for is to surprise people.