When I've needed to return drives, I've simply shown up at the store where I bought the drive - they have their own RMA procedure. Sure beats having to ship to the hardware vendor.
Once, I did
send a drive directly to maxtor, though. First, I made sure the drive really was
dead (hook up to old PSU, short-circuit the PCB with a screwdriver). Then followed their RMA procedure, put the drive in an anti-static bag, wrapped some polyfoam/whatever around it, put it in a decent cardboard box, and added some balls of wrinkled up newspaper until the box was full.
Appearantly, that was good enough. Iirc maxtors european department is/was in .nl, and the package got there safely, and I got my replacement.
Thing is, and that's why I prefer buying from a decent store that'll swap a dead drive with no questions asked, is that maxtor sent me a damn refurbished
Dunno about new warranty periods when getting RMA... I think with the "back to shop" strategy I now employ, I get a full new warranty... but only the 2-year .eu whatever warranty thingamajig.
As for drives... go raid-mirror for your important data. While it's not a replacement for backups, at least it reduces the risk of data loss. And do make sure the drives are being kept cool, having a silent 80mm intake fan in front of your drives does wonders for lifetime.