Just because you haven't heard of it doesn't make it bad. Nod32 is one of the best AV's out there, I use it myself, and it's very light on resources (unlike Norton).
Count the time it takes to boot your system with Nod on it, then take it off and put Norton on and count the time... you will see your boot times and general response times doubled! That, coupled with the fact that Nod can match or beat Norton's detection/removal rates makes it the obvious winner, (in my book).
norton has a really good user interface, which is part of the reason more ppl choose it. I like norton, only thing i dont like is that it uses alot of system resources.