If you are looking for a card reader to get your footage on to a computer, it is worth knowing that not all card readers are the same.
I recently bought a £20 card reader from PC World, the guy in the shop told me card readers were essentially just a bit of plastic and that they would all download at the same speed, depending on the card speed and the computer. I plugged in the card reader on a shoot with a full 18 gig CF card and it took close to 45 minutes. Since we were shooting approximately 4 hours a day or 4 x 16 gb cards this was a total pain. When I plugged in the camera, it was able to transfer the same card in around 15 minutes. However, from my experience, card readers are a lot more reliable than copying straight from the camera, sometimes the card won't even copy from the camera, and the card reader seems to cope fine.
I looked around for a new card reader, but everything advertised itself as being "fast" without giving actual speeds. The Sandisk ImageMate® All-in-One Reader/Writer advertised speeds of "up to" 34 mb a sec so I thought I'd go with that and test it out. I bought it from Amazon for £25 so a similar price to the first one I bought. I just downloaded a full 16gb card in under 8 minutes so about twice as fast as my camera and over 5x fast than the card from PC World.
FUll 16 GB CARD download times:
Puremedia Multi card reader from PCWorld: 45mins
Direct from Canon 7D camera: 15mins
Sandisk Imagemate: 8 mins