You need admin privileges to disable the Adobe Reader 7.0 Plugin, first you need to log in as Adminstrator and launch Adobe Reader 7.0 and choose preferences (cmd-K - nonstandard), down in Internet unclick the first two items.

Problem is when you log into a non-admin account Reader 7.0 will ask for admin username/password so it can install Frameworks in Safari. If you can't or won't Adobe Reader quits.

So you need to set the preferences in an admin account before you use Reader 7.0 in a non-admin account; otherwise, remove \~/Library/Preferences/com.adobe.* in the non-admin account.

If you can't get the Internet preferences disabled in Reader 7.0 in the non-admin accounts either copy an admin preference file "com.adobe.Reader7.0.plist" or try editting that file using the Property List Editor (if you installed the Developer Tools).

Under the section Originals, look for BrowserCheck and BrowserIntegration. If BrowserCheck doesn't exist select Originals and clcik button New Child, change the "New Item" to "BrowserCheck", change it to an array, then expand the disclosure triangle and press New Child, change it to "Number" with value of 0 and hit "New Sibling" button and change it to Boolean with value of No.

If you convert it to text you would get:

<key>Originals</key>
<dict>
<key>BrowserCheck</key>
<array>
<integer>0</integer>
<false/>
</array>

Next do the same for BrowserIntegration if it does not exist.

Preventing Adobe Reader 7.0 from messing with Safari is very hard, perhaps impossible. The closest I came was by "fixing" "com.adobe.acrobat.sh.plist", open with property editor and change "NoSelfHealNeeded" to "Yes". Problem is that Adobe Reader will undo this everytime it is launched unless you get fancy with the premissions of ~/Library/Preferences (simple changing of the premissions of this file is bypassed by Adobe Reader 7.0).

Reader also installs a plugin directory in /Library/Internet Plug-Ins/.

The ends that Adobe will go to to modify your non-Adobe applications should give serious reason to avoid using Adobe Reader.