There is no way to permanently remove or hide apps on the Android market, even if you don't want them any more and they were free. The system remembers that you "bought" them, even if you didn't have to pay, and you can get them again for no charge. Great for paid apps, but not so great for free rubbish you didn't like, or for apps that are not compatible with an upgraded/replaced device. My own history even includes one that is now obsolete, replaced by a paid version. Anything you ever installed on an Android device, even for a minute and even after you uninstalled it, will get the same prominence as something you use every day, at least as far as the market is concerned. There should be a way to make it forget.
Mokalus of Borg
PS - Your purchase history doesn't need to be your app install history.
PPS - Especially for free apps.