Mine did come with a USB cable, from ProCameraShop. However, I never use it and like others here I've got a dozen spare from other canons that would do. Card reader chap myself so after a shoot I transfer using a card reader to the laptop or PC just using Windows Import into a dated named folder. I then back up straight away onto a portable drive. I don't tick the box to erase after import in case something goes a bit pear shaped, which does happen.
Once I'm sure its all transferred and backed up I then reformat the card in camera.
For processing I use LR4, CS6 or PSE 11 or a combination. Once done I resize the ones I like to 300 dpi for printing and 72 dpi for the WEB. I rename them with the prefix PRT_ for print and WEB_ for Web. I've also introduced a new prefix BF_ for Bird forum

All get saved to the original folder then backed up again. Probably a bit paranoid about losing an important shot, which I've also done.
For the iPad I've been using a camera connection kit but have found you can only import once from an SD card. If I try adding files to an SD an then try importing to the iPad it doesn't want to know. So, to transfer from PC or Latop to iPad I've been using Dropbox which I've found really handy (free up to 2.5GB)