I don't know if we can neccessarily be ready for everything. On the other hand, i think alot of virus/trojan news can be sensationalist(as is the case with most news).
Here is my experience with viruses and trojans.
I worked at an ISP for a while. Most customers who called about having problems with viruses and such had stupidly opened a file attached to an e-mail from someone they had no previous contact to. Most often, the e-mail stated that the attachment was pornography(that is, when they admitted to this). I don't think it takes a brain surgeon to know that you shouldn't open attachments from people who you don't know.
I myself have never really had a problem with viruses. I never have went out of my way to search for them. If i do have any virus or trojan on my computer, i haven't suffered any adverse affects as a result of it. I'm not neccessarily reccomending this to anyone, because it's out of pure laziness, I assure you.
If anything, the real thing that fights viruses is knowledge, not software.