AntiviRus

ESET NOD32 Antivirus Software offers superior, comprehensive protection, the fastest scanning throughput, and the least performance impact of any solution.

Symantec provides free download of latest antivirus definitions manually. This would be very helpful for users who are not directly connected to internet, so that they cannot run live update.
To download norton antivirus definitions manually.

DownLoad Link
http://www.symantec.com/avcenter/defs.download.html

The 2008 edition of VirusScan Plus integrates antivirus, firewall and anti-spyware capabilities and contains (amongst others) the following features:

On-access file scanning
Inbound and outbound firewall protection
Spyware protection
Daily definition updates (except the weekend)
Daily pop-up reminders, appearing at random intervals, even over full screen applications and video games. This feature cannot be disabled.

* Improved performance delivers faster starts and scans. NEW
* One click access to expert support. NEW
* Network security monitoring helps protect your wireless network. NEW
* Norton Identity Safe delivers enhanced i dentity theft protection. NEW
* Works quietly in the background. NEW
* Protection for up to 3 PCs per household
* Blocks identity theft by phishing Web sites
* Protects against hackers
* Detects and eliminates spyware
* Removes viruses and Internet worms automatically
* Protects email and instant messaging from viruses
* Prevents virus-infected emails from spreading
* Rootkit detection searches underneath the operating system using patented technology
* Includes protection updates and new product features as available throughout the renewable service period *
* On-going Protection option automatically renews your subscription **

System Requirements:

* 300MHz or higher processor
* 256MB of RAM
* 350MB of available hard disk space

Download
Serials

Kaspersky Anti-Virus v.7 combines traditional antivirus and antispyware defense methods with the latest proactive technologies to provide solid and dependable protection against all types of malware. This award-winning antivirus & antispyware software includes protection against viruses, adware, spyware, Trojans, Worms and keyloggers and features automated hourly updates.