If UAC is disabled, aren't standard users still prompted for an admin password for the same types of events that UAC would pop-up when it's set to "always notify"?
No. Standard users simply get an "access denied" or something like that. Programs that rely on admin permissions either fail or cannot perform all of their functions. You can use "run as another user" manually to switch to a specific user when needed, but Windows will not do on its own.
With UAC enabled you get those notifications, admin users get prompted for yes/no and standards need to supply a user/password. Also poorly written programs get file and registry virtualization for helping compatibility and the secure desktop for entering passwords.
Great answer.
As alejandro85 stated, turning uac off and running as a standard user would in a sense be like windows xp was running as a standard user. Access denied messages everywhere when attempting anything adminstrative on the pc. This is why UAC is good to have on, it encourages you to use a standard user account.
User account control (UAC) protects the system in many ways.
In windows vista and above, the admin account has the same rights as the standard account. The only time the admin account is elevated to admin is when the uac box appears and you click yes to allow the action, which elevates that process for a short time until the action is complete. When copying or changing any folders in examples below, you must click continue (vista) or yes (windows 7 ^) to allow a rename or delete of a folder, etc.
UAC protects multiple areas, here are some of them:
-registry
-installing/uninstalling programs
-program files folder
-windows folder
-other user accounts folders
-temp folder/app datar
Read up on it here:
User Account Control - Wikipedia, the free encyclopedia
UAC info for IT professionals
Why use a standard user account instead of an administrator account?
When using a standard account and you make a change or install a program that affects the whole system, UAC will prompt you to continue. Make sure the setting or program you are tying to install is listed, then click yes to continue. If you are just browsing the web and the prompt appears with a program you have not heard of, or do not know what it is, it is much safer to click no then yes. No will block the action, and if you were trying to do something, you can always start it again and choose yes.
UAC makes this easy, see here:
What is user account control (UAC)?
I also suggest choosing always notify for UAC for better security:
What are User Account Control settings?
The above link clearly explains the differences between the uac settings.