I've been running Windows One LiveCare for a long time, and thought I was doing okay until my laptop got infected with a really nasty trojan recently. LiveCare didn't even detect it; I only became aware of its existence because it prompted me to install new software and I was suspicious. John and I worked together for three days to get rid of it, trying various programs, strategies, and work-arounds -- none of which worked.
In the end, I got Spyware Doctor, and that solved the problem -- though not immediately. At first, Spyware Doctor was able to quarantine the trojan but couldn't delete it. One night while I was at work, John ran LiveCare Cleanup -- which, as I understand it, completely removes LiveCare from your PC. The trojan went away. The next day, it came back, but this time Spyware Doctor was able to delete it. So far, so good. That was about a week and a half ago. Spyware Doctor also found all kinds of other stuff lurking on my computer; John said he'd never seen any computer so infected.
I'm guessing from this that some viruses are written to deliberately exploit weaknesses in LiveCare. At the moment I'm running Spyware Doctor and Registry Mechanic. I do a scan at least once a day, usually more, and only once have they found nothing. Most of what they do find are identified as low-risk, legitimate programs that I "may not" want on my computer, but they've found a couple infections they designated as high risk.
Anyway, I'm happy with Spyware Doctor for now.