Personally, with any new AE installation I download all the latest plugins and run the installers as intended. It's reliable, and guarantees you're using the latest versions.
To Access the User Library folder in Lion simply hold down the Option Key and click on Finder>Go It's right there. You can also use the Go>Go To Folder (Shift + Cmnd + G) and type ~/Library in the pop-up to go to the User/Library folder.
To Access the MacHD Library (system) you just need to gain access to the root directory of your system hard drive. You can go there by using the Go To Folder option and simply typing / in the pop-up. You can have the system HD always visible by going to your system preferences.
If I know that I have the latest versions of all plug-ins sometimes I will create an alias to ones that don't use installers. If a plug-in has an installer I always use that.
Hope this helps.
Thanks for the tips guys... went the installer route.