Well, I have clearly obsessed over this car more than any other.  First a paint chip, which I obsessed over for like a week, then a door ding, which took a couple of days of obsessing.

Now my xB has developed the dreaded passenger-side creak at 2 months / 2900 miles.  Searching around the Scion forums, it seems that many have experienced a creak/rattle in the passenger side a-pillar and a few in the b-pillar.  Mine is coming from either the passenger side b-pillar or door, can't tell exactly.

It's not constant, but frequent enough and loud enough to bother me, so I think I'm going to take it in.  Actually, the first time I noticed it, was OVER the sound of the radio.

The same thing happend to me L0stS0ul. The dealer took care of mine too. But it was a little disheartening to see all that on my brand new car.

Update:

Took my car in this morning.  When I described the problem and told them I was going to wait on it, they kind of hemmed and hawed and said it could take a long time, “these things can be difficult if not impossible to pinpoint”, etc and said he couldn’t promise they’d be able to fix it at all.

Well, despite all that and my own pessimism and skepticism and general lack of trust that anything out of my control is going to be done right (especially regarding car dealer service), I have to admit that I came away from the dealership as a satisfied customer.  They came in under the amount of time they said it would take, and they seem to have fixed the problem.  I was fully expecting them to say that they either couldn’t hear the rattle (and therefore couldn't diagnose it) or could hear it but couldn’t find the source.

They said that the technician heard it too, and quickly identified it as a very slightly loose striker plate on the passenger side door.  They tightened it and… no more noise.  I only wish I’d have checked that part myself; could have saved an hour or so of my life...

I'm glad you got your rattle fixed. I got my car back from the dealer and they only fixed 1 of the scratches and told me that they can hear the rattle but they can't find it so I'm stuck with it until it gets worse.