In this modern world you can’t think of using your machine without any anti-virus software. Choosing a good antivirus both in terms of cheapness and high quality is a difficult and uphill task. Below are the some of the good antivirus recommended for MAC OS.
ClamXav: This is free software. The new ClamXav 2 allows both processes to be scheduled and run automatically. This is build for both PowerPC and Intel-based Macs running OS X 10.4 and up.
Sophos Anti-Virus for Mac Home Edition: This is also free software. This is fast and allow full system scans in small time. This is basically designed for OS X 10.4 and up, both PowerPC and Intel chipsets.
PC Tools iAntiVirus free for basic version: Many PC anti-virus software vendors offer limited free editions of their paid products, then keep bothering you to upgrade and pay for the full version. This company, based in Ireland, also does so for the Mac. But the free version isn't bad, permitting you to schedule definition updates and scans, as well as customize scans. If you want to pay $29.95 for a year's subscription, you'll get free 24/7 support (and turn off the constant nags to upgrade). This is for Intel-based Macs only.
Avast! Mac Edition $39.95/year: It runs on both chipsets, OS X 10.4 and up. For an extra $10 per year, you can get the Mac + PC edition, which protects the Windows installation on your Intel-based Mac as well.
BitDefender Antivirus 2011 for Mac $39.95/year: It also has Bit-Defender adds anti-phishing protection to the usual features and has a "Mac and PC" combo option that costs $10 more. Both versions are Intel only.
Kaspersky Anti-Virus for Mac $39.95/year: This is famous Mac product offers "cloud-based monitoring of websites and applications," which increases protection against suspicious sites and apps. There's no "Mac plus PC" option, and it's for Intel-based Macs only.
Panda Antivirus for Mac: It guards "against viruses, worms, Trojans, spyware, keyloggers, bots, and other malware attempting to access your Mac." It also "detects banking Trojans" and protects your "iPhone/iPod/iPad."
Intego VirusBarrier $49.95/year: This Mac-centric company wins lots of "best of" accolades for its Apple-only security products. The latest version of VirusBarrier offers a two-way firewall which scans outgoing as well as incoming traffic, and also monitors running applications for suspicious activity. For an extra $30 per year, Intego Internet Security Barrier adds parental control and backup features, and $10 on top of either package brings along Windows protection. The latest versions require at least Mac OS X 10.5, but appear to be chipset agnostic. Support for earlier versions of VirusBarrier is available all the way back to Mac OS 9.
McAfee Internet Security for Mac $79.99/year: One of the big boys of consumer anti-virus software, McAfee was recently bought by Intel and as such their latest Mac product runs only on Intel chips. It's all-encompassing, rating websites for safety as your surf the Web (Firefox only) and running its own firewall. Yet the Web page is short on specifics, and it's not clear whether the extra bells and whistles are worth twice what you'd pay for one of the Eastern European vendors' products.
Norton AntiVirus Version 11 for Mac $49.99/year: The General Motors of anti-virus software takes Macs seriously. Its AntiVirus Version 11 for Mac automatically updates definitions, runs scans and screens new files and attachments. (Then again, so does the free Sophos app.) A better value is the $79.99 Norton Internet Security for Mac, which adds a two-way firewall, file encryption and network and browser monitoring. "Dual protection" options for Macs running both OS X and Windows are available for both AntiVirus ($69.99) and Internet Security ($89.99). For both PowerPC and Intel-based Macs.
UPDATED: Finnish security company F-Secure released its F-Secure Anti-Virus for Mac on Thursday just as we were publishing this story. The application features a "panic button" that immediately blocks all network traffic and uses a cloud-based malware-definitions library. It costs about $45 for a year's subscription and runs on Intel-based Macs only.