Check this forum for similar threads. I think many have mentioned their usage as that of a UPS+ Surge protector. Calculate the usage of your system and then go for a UPS that'll handle the load of the entire system.
Personally, I run my Sony 42W70B + YHT299 and Modem+Router through a Belkin Surge Protector. Since I do not face many outages in my area (fingers crossed) I just have safe guarded against power surges.
If you have many outages in your area or face fluctuations go for a UPS.
You don't HAVE to go for anything, but it never hurts to be on the safer side
Happy Listening
I use a V-Gaurd crystal stabilizer and then connect a Surge protecter to the stabilizer for taking multiple device input. Do not connect your HT directly to the power.