In the new App World released today, 2.0.0.36, the uninstalled apps no longer appear in My World.
Interesting...2.0.0.26 still shows them... Although it's a bit confusing - because it doesn't seem to be aware of a number of apps that are actually reinstalled on the device, and still shows them as uninstalled. Seems they never quite got it to be able to examine installed programs if they weren't installed via App World... a shame -- really limits usefulness of the feature.