Recomended fast USB hubs for Imac

[Louie Angulo <louie.angulo@googlemail.com>]

ok gang,so ive runned out of usbs in the back of my Imac,after pers
recomendation i also bought the soundtoys plugin bundel which is
absolutely awesome but requires a usb authorization stick to be
plugged in
im also moving all my native intstruments sound libraries and samples
to an external WD 500GB usb portable external drive.
ive never owned one so i dont know if there would be drawbacks and
disadvantages as far as speed is concerned pluging the external drive
into a usb extension .
If quality is crucial could you then recomend me a good and fast usb
hub for that?
many thanx!
Luis

-- 
www.luis-angulo.com