Civic - Honda :: Resonant Noise - Bad Wheel Bearings?

After my Chevy Prizm took its rightful place at the junkyard two months ago (transmission failure on a car with a bad engine and suspension problems is, and should be, fatal), I got a 2008 Honda Civic to replace it. I had it checked out before buying by my mechanic, and I've driven it a few thousand miles without many issues. It had just under 42K on it when I bought it (former lease bought at new car dealer sale by the local place I bought it from), has just over 46K now, and has new Bridgestone tires on it that my mechanic says are worth $700-800. (I don't know exactly what kind they are, which is why I include that bit of pricing info.)

Last week I noticed that a sound I'd been hearing intermittently (to the point where I wondered if I was imagining it) became steady and consistent at 60mph. It's a "hooooooooo" sound, very resonant, and it's driving me crazy. It's gotten louder and louder, and it's now happening around 30 mph and above. It's been consistent since last Friday and getting worse every day.

Underneath that sound is the soft drone of what I assume is a wheel bearing going bad, which is still intermittent and has only started in the last few days. This is what causes me to believe what my mechanic said yesterday, which is that one of the front wheel bearings needs replacing. He also said I could wait until the sound "gets louder" before replacing the bearing -- I assume he means only the droning sound, not the resonant hooting that I hear every time I get onto a main road now. Because I believe the resonant sound COULD get louder, but I don't see how a person could keep driving under those conditions without actually going insane.

I scheduled the car to go in tomorrow to have that bearing fixed (for between $300-500, he said, which seems really pricey to me). But I'd like to know whether this is likely to solve the resonant "hoooooo" sound as well as the "wow wow wow" sounds that I associate specifically with a bad wheel bearing. My mechanics checked the suspension and rotated the tires yesterday while doing an oil change, too, and said everything looks tight and good, and the tire rotation had no effect on the sound I'm hearing, which is strongest from the driver's side front and is, again, louder every day.

(I know Civics aren't supposed to be great on road noise, but the fact that this has clearly gotten measurably worse over only a few days makes me feel its definitely mechanical and not just the usual ambient highway noise.)