tinpis
Things I find great about Avast:
-It's helped keep my computer clean for about two years.
-It's effective.
-The forum membership is responsive and very helpful.
-"boot-time scan".
The not so brilliant (but definitely willing to live with it)
-No scheduled scanning in the Home version
-The interface navigation takes a bit of learning. Worth it, though.
I think you'll be quite happy with it. Not to mention malware-free.
Demand scanner is also recommended. All the AV's can occasionally miss one "on the day".
Highly recommend MBAM and/or Superantispyware. Both (free or paid) antispyware applications, with a very good rep.