Hi Tigersjaw,
I am a Carleton Alumni so I'm familiar with some of the areas you might be interested in. I lived in the South Keys area, which is on the O-Train line (the train that runs right through Carleton Campus). I think it's a particularly good area due to it's proximity to Loblaws, Walmart, clothing stores, Bank Street, a bunch of parks and best of all, it's affordable. As you might expect, it is a little far from Downtown Ottawa, however, it's close to the airport.
To summarize - its a great price-conscious, safe and convenient area. It's not great if you're looking to enjoy Ottawa night life or working downtown/Parliament.