User Account Control has been significantly improved to be both less intrusive and smarter at distinguishing between legitimate and potentially malicious activities in Windows 7/8. However, depending on whether you are logged on as administrator or a standard user, some installs of Windows may have a default UAC security setting that's one level lower than some experts recommend. Standard users have UAC security default to the most secure setting, while administrator accounts reside a notch below the highest setting, which is potentially more risky.
Microsoft created an easy UAC slider bar to allow administrators and users to adjust their UAC security level. After installing all the initial software and configuring Windows the way you want it, you should raise the UAC slider bar to 'Always notify', the most secure setting. Even in always notify mode, you'll encounter fewer UAC prompts than you did in Windows Vista.