Solved first questions about windows 8

[oneeyed]

Check this : Zero Day | ZDNet
This still applies to win 7/win 8. UAC isn't a security boundary, LUA is.

Security: Inside Windows Vista User Account Control

Even though elevation dialogs appear on a separate secure desktop, users have no way by default of verifying that they are viewing a legitimate dialog and not one presented by malware. That isn’t an issue for AAM because malware can’t gain administrative rights with a faked Consent dialog, but malware could wait for a standard user’s OTS elevation, intercept it, and use a Trojan horse dialog to capture administrator credentials. With those credentials they can gain access to the administrator’s account and infect it.

From : http://download.microsoft.com/downl...rity_Best_Practice_Guidance_for_Consumers.doc

Good Practice: Create a Standard User account and use it every day!

When setting up a system, you should make only the first user account an Administrator account, even on a child’s machine. Be sure to choose a good password to protect the Administrator account. By default, this first account had approval mode enabled, meaning it can be used to configure Parental Controls and manage any setting on the system. All subsequent user accounts you create —especially for kids—should be setup as Standard Users. If a user with a Standard User account needs to complete a restricted task, installing a program for example, the Administrator can enter the proper credentials to complete the task.

For normal system use you should be able to login as a Standard User, and enter your Administrator credentials only when a task requires it. Taking this extra step when you need it will help prevent accidentally doing something you didn’t mean to do – or installing something you know you shouldn’t.

Anyway it's a trade between convenience and security. I still think it better to run as limited user for browsing/checking mail, etc...