EEK is a hefty download and (IMO) not worth it, unless you're constantly troubled with malware.
Malwarebytes Anti-Malware should be sufficient for on-demand scanning, for a second-opinion HitmanPro (no need to activate it, un-check Cookie scanning).
http://www.malwarebytes.org/products/malwarebytes_free/
http://www.surfright.nl/en/hitmanpro/
Free Antivirus, I have used and/or recommend (not in any order) :
- Avast Free Antivirus
- Bitdefender Free Antivirus (registration required)
- Microsoft Security Essentials
- Panda Cloud Antivirus Free (toolbar can be uninstalled and still have web protection)
Or try this, Norton for 6 months (Paid AV, but 180 days free) :
http://malwaretips.com/Thread-Giveaway-UPDATED-LINK-Norton-Internet-Security-2013-180-Days-Key
At the end of the day, you could have the "BEST" AV or Suite and still get infected.