I don't have time for a long essay which will answer your question IW, but the short answer is no.
The most vicious malware uses social engineering to get you (or you grandma or your 13 year old) to click on either something they don't read or something that sounds innocent or mildly confusing. It then installs a dropper and opens up avenues for other nasties to enter. This will bypass firewalls, routers, AV programs (both commercial and free with equal ease)
Turn off applications in facebook, scan with malwarebytes antimalware and super-antispyware regularly and be prepared to reload your computer OS from disk or recover partition and back up any music, pics, docs and PST files you don't want to lose.
The big AV comnpanies, and os makers are losing the battle (to be fair, MS created the petri dish long before it started trying to fix it)and it is every computer user for himself these days.
I see infected machines with every AV version out there, updated and running. The commercial versions have no edge over the free except that they automatically update and run on schedule, which many users defeat by setting the run time to when the system is usually turned off.
Adobe has not released a version of reader or flash that was not immediately discovered to be vulnerable since 1997. adobe X has some interesting "sandbox" features but it is new.
BTW adobe reader 9 will not automatically (or through the "check for updates" menu) to adobe x.
http://download.cnet.com/Adobe-Reader-X/3000-10743_4-10000062.html