Haven't looked aty it myself as I use free programs not trials. Most trials are usually only for 30 days and after that you have to buy it or remove it.
Its up to you what you choose, if you want to go free then a free firewall and antivirus will do or you could even use Vistas firewall as I believe it is much better than XPs one.
If I was going to buy a package, and personally I don't see the need, but if I was I would be looking at Kaspersky click here the only reason I say that is that in all the tests I have seen over the past year or so they are rated as about the best. The only other one I would consider as a purchase would be NOD32 click here
If this is what you're on about click here it states quite clearly its a 15 day trial.