Based upon a very small sampling, I wouldn't worry about it at all. We (well, I) bought a dirt-cheap HD LCD this summer for eventual college use next year. Just went checking that & all the other LCDs in the house - the only noise I could hear was from the el cheapo and that was only a very faint florescent light-like white noise when the backlight came on and that lasted for at most 30 seconds. It was not detectable at all by the third time I turned the TV on, and I was maybe 12-15" away to be able to hear it at all. You should be able to try the on/off test in the store but I'd wager you'll hear nothing, too.
I'd agree w/ Pdn - check for features you want. For 720P @ 26" practically anything will work OK - and if I'm remembering the right one then the 26S3000 is a very nice unit that had decent blacks, too. Looked way better than the plasmas ;~) (for those of us who hate the obvious screen door from most plasmas).