You could daisy chain a couple UPS's I guess. I just run gear that runs on batteries. It's a PITB at times, but not having to stop what you're doing to find a different plug is cool. But my setup only has 4 juice needing devices at the point of capture. I use a laptop to edit, so it comes with a built in battery backup. Just a camcorder, field recorder, and two one channel external microphone preamps running on batteries.
You mainly need the conditioning for the analog audio chain as dirty power will add noise to your signal. That's where the sine wave inverter comes into play. But it really is a where you live thing.
I had the fuse on the pole outside blow and the week(s) prior to that the fan on my desktops video card was extra noisy. After that got replaced because it blew, the fan on the computer was quiet again. Or at least quieter. Quite a bit quieter. Otherwise all I've got is a surge protector. I do notice the lights blinking every once in while, otherwise the power company only messes up noticeably once every six months or so. When the fuse went, I was without for over twelve hours. In part because it blew about midnight and no one was heading our way until business hours. Fortunately with battery powered gear, you can still capture when the power is out. It's almost eerie how quiet it is when the power is out. No fans, no buzzing electronics, no A/C, not fridges and other things. You can hear the birds landing on the rooftop and other things otherwise ignored.