I used to hate on Norton like everyone else in this thread.
I bashed it every single chance I got.
Bloatware, useless, heavy, "as bad as the viruses it claims to stop," etc...
Then I started having issues with NOD32. Issues that were brought up repeatedly at WildersSecurity in their recognized support forum, only to be discounted by their reps.
So I had to ditch it. Either that or ditch Firefox since I could not download any file that was compressed in anyway without NOD screwing it up.
People told me to give Norton a chance, but I dismissed them and tried numerous AV offerings, only to have problems with each.
Finally, I gave in and tried Norton AV 2010.
Immediately, I noticed 3 things.
First, it installed so fast that I was sure something had gone wrong.
Second, it didn't even suggest that I should reboot.
Third, nothing seemed slower on my PC.
Everything I had hated about Norton security products had been fixed.
Bootup times did not take a noticeable hit.
File transfer times were just as snappy.
Hard drives didn't thrash.
False positives didn't cripple my programs and utilities.
Everything has been so great since I gave Norton another shot that I recently I upgraded to Norton AV 2012 for all Windows PCs in my home without a second thought.
In fact, I even recommend Norton AntiVirus to friends and family without pause.
My Norton protected computer runs without a hitch.
What more can you ask for?
Total working set size for Norton AntiVirus 2012? 22mb.
CPU use? Non-existent unless I am running a full scan.