Tranglos, I'm curious, did you ever settle on an antivirus suite?
Yeah, I did go with Kaspersky, thanks for the suggestion. I chose the AV, not the firewall (which I liked, but decided to go without). I really like the UI (I'm a sucker for nice UI's, so that was easy), and I see no delays when opening/viewing large files. I had that problem with ESET, where the real-time AV would cause perceptible delays e.g. when viewing files in Total Commander's lister, or copying various installers between folders. Kaspersky seems faster here, and I'm quite satisfied with it.
I've discovered how to exclude files by extension, which wasn't immediately obvious to me: in Settings -> File Anti-Virus -> Threats and exclusions -> Settings again. I needed this because after installing the AV I started getting strange crashes from an application that often updates a large MS Jet database. It was throwing unlikely errors like "disk or network resource is no longer available", then crashing and taking some of my work with it. It suppose Kaspersky was scanning the DB in real time (on every access?) and maybe was locking the file, who knows. It seems to have stopped after I excluded the specific extensions from scanning.
I've already found a likely false negative
too. I received a piece of spam with a typical come-on message and a zip file containing a randomly named .exe file. No idea exactly how harmful it was, but definitely not something you'd want to run. I unpacked the zip file, but Kaspersky gave no peep when viewing the exe file, copyng it, or scanning that specific file. Of course in the past on occasion I did the same kind of experiment with ESET, and it didn't flash the red light at me, either. Maybe I should turn on heuristics, after all