I have a 40Gb HDD on a USB 2 port. Recently I backed it up to my internal HDD, It took 9 hours! So I wouldn't recommend using USB drives for anything other than backups. I only have it because it was a spare drive with no other home.
If I buy and fit an internal DVD recorder I presume it would be quicker than the external type but also, would you think that an external Hard Drive is better for complete back up than a DVD recorder anyway?
joethebow, something not right here, maybe you external HDD works on usb1 mode even it is a usb2 device, I do 120GB HDD cloning to external usb2 HDD only takes around one hour
Internal DVD writer is quick and much cheaper and you can get very high quality and fast one around £45.
Back up to external HDD is very very fast (if you fit a usb2 card) and it takes a lot more than a DVD disc. But if it goes belly-up, a large number of data gone. If you use DVD you can do double or even triple backup as DVDs only cost around 30p (quality ones) even you buy bulk. Even if one gone, only 4.7GB affected.