[GrimUpNorth]

I've got the same router as you and have had an external drive on the go for maybe a couple of years. I go on the logic that it will fail one day and I make sure I've got a copy of everything important somewhere else (eg on our home network, or better still in a different building, or both!).

I'm using a WD drive, don't think it spins down, but it's upstairs so can't hear it. One thing though, the router's only USB2 so it's not the quickest option.

Hope this helps.

Cheers

Grim