Anybody had the need to replace their wheel bearings?

[Mcbruges]

Car: june 2005 3.0i

KM up to date: appr. 33000 km (20k miles).

Symptoms: slight roar in the rear.

The car is driven hard/fun but far from being abused. The roads in and around Calgary are not Autobahn quality but neither are they extremely horrific. All in all, the way the roar appears to the ear while rolling at higher speeds, I'm pretty sure it will be the wheel bearings. Anybody had their wheel bearings go after 20K miles?? I know on our X5 they've needed replacement multiple times in the last 150K miles, but then again the X5 is much heavier than the X3.
I'll be making an appointment today, I'm sure it will be under warranty but still for a vehicle of this price BMW......