Sean, my Radio Shack plug-in AC meter is genuine plastic, not the fake kind, and is pure analog with a pointer, green and red zones and everything! Cost me almost $10 about twenty years ago and it is plenty accurate as it was the cherry picked audiophile version......Good news here is that the fifty year old transformer on the pole in my back yard finally blew up a couple months ago and now the power doesn't dip below 110v when I run the air conditioning here (yep, it has been on already this year as it was 86 ten days ago)........
Back to the original question, I think a couple dedicated lines, one for digital and the other for analog, will do more than most any line filter......Homeowner's insurance will pay for lightning damage to gear so see little reason to do much other than turn it up during a storm......It really depends upon where you live if a line filter would be appropriate as most are set up for worst case and beat the poor AC to death.....Those in metropolitan areas will need a box full of lots of little caps to null out the nasties and those on the outskirts of metropolitan areas or those in rural areas just don't have the same sorts of problems with their AC......No clear cut solutions other than it is really easy to overdo things.........
Bob Crump
TG Audio/CTC Builders/DDR Mfg