Well, just about any paid solution from a known supplier is good, really.
I took Bitdefender, for example, they have this nice Autopilot mode, where it does stuff by itself depending on what you do, it automatically switches between gaming mode and general and such. It seems to be lightweight, but my system is pretty powerful.
As antivirus, I have no complaints about it.
But really, just look for a decent deal on any good antivirus and you will be ok.
Edit: And I just noticed that you have Bitdefender and don't like it... just kill it and trial something else, you don't really need to pay to try and see how it goes.