Thanks Lazarus .... but YMMV. Some of the reviews of this Akasa hub suggest that it may not be able to handle more than one hard drive. The reviews on Amazon tell a similar story about many other brands too, although the MaxValue 13-port hub seems to perform better than most.
Some websites suggest that the design of hubs varies: in theory each port needs to be able to provide 500mA, but in many of then only one or two ports provide full power and it is assumed that other ports will be used by flash drives etc which need little power.
I found a US website at http://www.brighthub.com/computing/windows-platform/articles/1756.aspx which reviews some models. But the problem is that detailed spec on power-supply is rarely provided in the descriptions of the hubs currently on the market. So any expert advice on the power-configuration of hubs would be welcome.