I use Symantec corporate. It does both viruses and spyware, real-time protection and custom scans. I've used it for years and never had a problem. Actually, it's never even caught a virus b/c security patches basically have me covered.
I used Trend-Micro. I love it. I work in one of the Symantec Branch offices. I get so many calls from people who renewed yet the software does not update or recognize they paid. Plus to talk to a tech support dude cost 29.99 per question.
That is good. It doesn't appear to come with real-time anti-spyware/adware protection though.
Before Symantec Corporate included a real-time anti-spy, we used their other program, Webroot Spysweeper, and had great success with that. It was a pretty big memory hog though. Many times it had to be removed and reinstalled because the current version would take up 95% of the CPU when it wasn't even scanning.
In the past, I've used Norton, Kaspersky, AVG, McAfee and PC-Cillin. None of them come even close to Nod32. It takes practically no system resources and it's stunning how fast it scans. It's really amazing, actually.
I buy it in a pack with my Mom and brother so it's even cheaper that way.