I delete unwanted apps with the jiggling x, but they promptly reappear the next time I open launchpad. How do I delete in Lion?

I'd suggest removing the unwanted items directly from your Applicaitons folder. In order to do this, you'll need to highlight the desired applicaiton, then use File -> Move to Trash (or CMD + Delete on your keyboard).

If they're still showing up in Launchpad, or if they don't exist in the Applications folder, use the following command in Terminal to remove your existing Launchpad databases (as they may be damaged and not updating correctly) and restart Launchpad (which will create fresh databases):

rm ~/Library/Application\ Support/Dock/*.db ; killall Dock