No, it's shit. A pop up box asking me for permission to run a program every time I click an Icon is a total, stupid, piss arse, waste of my day....
If I didn't want to run media player, I wouldn't have clicked the 'Media Player' icon would I?
Your 100% right BUT what if a software lets say a spyware tried to open media player would "YOU THE USER" still want it to open???
UAC is used for that reason to ensure that the action was done by a human.
If you run an application which you trust 100% you can set it to "run as admistrator" by right clicking on the .exe and select the option.
Vista is good, the problem is that XP was so good, that people are afriad to change.