Having Accelerometers... 2
To be honest, the iPod orientation awareness often gets on my nurves. When it works OK, it's OK, although not everything supports it (If the OS says that the screen is landscape, then deal with it OK!)
When looking at photos, if I want to see a landscape picture, I can't unless I want to look at it on it's side.
If the thing is on a desk, or worse in a car / bus / boat / plane it seems to think it needs to change from landscape to portrait sometimes.
Following on from that, if _I_ am in landscape mode, I want the writing to be in landscape mode, so I can read it!
Conclusion:
It's a marketing thing, but hasn't been fully thought out enough