I'm running into an issue now that I had not anticipated when it comes to using the 7D. The files are freakin' enormous. Raw format at the full 18 million pixels are weighing in on average around 24 to 26 MB each.
The second hard drive in my Mac Pro, which is used almost exclusively for photos and video, is nearly full. The external bus-powered USB drive I decided to use for video, at 100 gb, is already full from stuff I've generated out of the 7D.
My online backup is now weighing in around 130 gigs, and costing about $23 a month. It's growing really fast all of a sudden because of the big photos. I don't actually backup any original video material to the Internet, only locally on my Time Machine drive.
I really don't care much for buying hard drives, but it looks like I'll need to do that soon. I noticed an external drive at Costco, a terabyte and a half, for around a hundred bucks, but it's not bus-powered. I like those because you don't need to lug around a power supply, which is super handy when you take it with you.