I'll chime in. I've used Avast Home and have been quite happy with it. At present, I use Trend Micro's Internet Suite Pro. There are a couple of reasons I switched. First, because it has internet filtering/monitoring/audit capabilities built in. While this isn't important for my personal machine, it IS important to give me the ability to monitor my 14-YO's internet usage.
Second, it also has some really great internet protection features over and above simple anti-virus.

In the interest of full disclosure, I received the TM ISP for free. I'm an IT security professional and was given a free copy from the vendor in an effort to get my company to purchase their product. While I don't think we'll be changing from our current product, I will re-up the license for my personal copies when they come due.