Avast! 5 rocks!!! I had just switched over to Avast! 5 Free Antivirus on the 29th of January 2010. Previously I thought Avira AntiVir and VIPRE were the fastest, but now I know what fast really means! Avast! is the only free antivirus which gives all the necessities of a paid antivirus(Web Shield, Behaviour Shield, File Shield, Network Shield and more.) Though I disliked Avast 4.8, I simply prefer Avast! 5 over Kaspersky, VIPRE, Norton, Avira, NOD32 etc. Keep up the good work guys! ;D 
;D
Just update from 5.0.396 to 5.0.418 in 15 mins on my dial-up connection.