Up/Daownloading via USB 1.1 can be grueling. A 1 gigabyte card takes about 17 minutes via USB 1.1, and about 4 minutes via USB 2.0. If all you need is a connection , USB 1.1 provides this. But if you are wanting to offload your camera, then it will become an annoyance.
The difference IS a big deal....if you can find a way to get a 2.0, that's the way to go.....also be sure that your PC has a "true" 2.0 port, these days vendors have found ways to "label" essentially a 1.1 as a 2.0. If you don't have a 2.0, there are inexpensive cards that can be installed in your PC to give the full 2.0 with at least 4 or 5 ports.
No, time really isn't an issue. I shoot jpeg Large on a 1 GB card. That's 286 shots..............and I've rarely shot more than 250 in one day. I want to buy the I/O Magic Digital Photo Library. I'm going to use it on a cruise in February. I'll shoot all day and when we get back to the room I'll download to the storage device while we prepare for the evening..............or even later. The difference between 4 minutes and 17 minutes is certainly not a problem. And I'm only wanting the device for this trip and will probably never have another need for it unless I'm on a trip some where away from my computer. Now I just wish I could find a supplier of the product. No one on the list on I/O Magics site sells them!!
One more thing to consider is how you transfer the files from the camera to the PSD, and which camera you have. My D70 supports only USB 1.1 speed, so transfering pictures can take a long time. My X-Drive, although certainly not state of the art, with it's builtin card reader has a higher transfer rate. On my last trip I used the cable link and transfered from camera to laptop. I found that this can drain the battery of the D70 much faster, so I had to charge more often.
If you shoot a lot and need a PSD during your shooting, time can be a very important factor. With more time required for data transfer, the number of pictures you can transfer on a battery charge goes down. (In that respect I wouldn't recommend the X-Drive - there are better options at the same price or less.)
So, if you own a D70 and purchase a PSD without card reader and don't intend to carry an external card reader with you, the USB1.1 is all you need. Just make sure you are able to recharge batteries in time.
Thanks for the tip..............but the I/O Magic Digital Photo Library has a built-in card reader and 20 GB hard drive. It has everything I need.....only it downloads slowly. No problem though..............(see past posts)