Not sure why we are all replying to an old thread.
AV software was pretty handily summarised by the bofh a while back
http://www.theregister.co.uk/2014/11/08/bofh_2014_episode_11/
Anyway adblock + something stronger if you/your client can take it (I go full requestpolicy and noscript, though the lesser option might be ghostery), keep flash and java off your system if you can, isolated* if they must be there (no external website should need java and if it does then consider not going there) and definitely keep them updated.
*if you want to go full virtualbox or sandboxie then go for it.
MSE/Defender works well enough in my experience (I do not want to fix viruses on computers and MSE does not seem to let in anything more than the others that people can stand to usee), and bonus is free for smaller businesses/setups. I am never quite sure of many of those stats that say it is ze worst, see the bofh linked as it all applies to ones I see.
For a client then teach them a good porn site (or just to use the good ones), a good torrent site for films, TV and music if they are inclined to torrent and say that programs are the crapshoot they really are.