I've always used ESET Nod32. In the old days it had the smallest footprint for performance stealing, and I've stuck with it. Nowadays with CPU cycles to spare, it probably doesn't matter so much... I do know that the current version of Nod32 has a 'Gaming Mode' that you can enable to prevent any weird popups, but I've never had issue with it and never enabled that mode.
Almost any antivirus software will suit you, so unless you have something specific you're looking for in an interface or features, it probably won't matter that much (provided it's a well-enough known product that's not a scam