Poll: Microsoft Forefront, Avast, McAfee comparison

Hi all,

I recently installed Windows 7 Final after i got the iso from my school-provided msdn account, but while i was searching through other software, I noticed Microsoft Forefront Client Security. I downloaded and installed it in place of Avast! antivirus, which i had been using for years.

My question is: as a student here, i have free access to Microsoft Forefront and McAfee antivirus, as well the free version of Avast!; Which software do you recommend i run, and why?

Many geeks here prefer NOD32 and Avast. I have used both with Win7 and currently using Avast Pro. Works well.