As for previous Q's about Zone Alarm, their firewall is one of the best, a bit of a pain to configure at first but it has become more user friendly recently. Once it is configured, that is, once it 'knows' what programs you'll allow to access the internet and vice-versa, its resource usage seems to diminish as well and it just does its thing. They've had an anti-virus for a while (which isn't free, which is probably why they can continue to offer the free firewall etc) and it seems to be well regarded. In May when my Norton expires I'll be switching to Avast (yes, i know, get NAV to uninstall itself) or AVG but will definitely keep my ZA firewall (btw, one of the worst foo-paws I ever assaulted my pc with was trying to un-install ZA, instead of just shutting it off, what a mess. If peeps choose aggressive programs like this best to learn to live with them and if you do choose to get rid of it make darned sure you know what your doing or look forward to a full re-format).
ERU, I seem to have gotten rather long-winded here but to address your question about Trend Micro, my curiosity is piqued so I'll have a look-see what the people at some of my fav security sites have to say about it. I'm sure there are others here who know more and will add their opines to this. I firmly believe you can't get 'too secure' in this day and age but you must be careful not to over-do it.