Is your default browser set to Firefox or Safari?
My default browser is set to Firefox 7.1.
Also, go to your home folder. Inside your home folder, open Library, then Preferences. Delete com.apple.help.plist and com.apple.helpviewer.plist.
Remember: I'm using 10.7.1*, so none of your proposals can be carried out. I can see all those items (including some others suggested for deletion in the X Lab article recommended by jchuzi) and even 'select' them; but deletion attempts result in the 'gong'.
* Library in home folder is 'hidden' (ie, not accessible); it can be placed (and made 'visible') under Favorites in Finder sidebar, but the system will not allow deletions at any level.
Ergo, I'm screwed. (What else is new with Lion?!)
