Hi,
I'm from Italy and I've just sent back to rma collection center in Milan 2 seagate 7200.11 320 Gb drives using a
normal box from postal service and a lot of
bubble wrap.
I've had no problems at all and the service was excellent. They received my box in Milan and the next morning they sent me a new couple of drives from Holland.
Firstly I packed the drives with their antistatic bag, then I used the wrap covering each drive and finally I packed all together with other wrap.
I only recommend you to use a not too small box and to use wrap to fill it, without letting drives move.
I don't know if I was lucky or if they are not so accurate, and if there are differences among different countries, but I hope to help you. ;-)