Well yes, they are great photos, but you can get the exact same results with the 20D as far as the look. The big thing about more mp, is that you can make a bigger enlargement. I normally get great results at up to 16x20 with the 20D. If you normally do larger than that, then the 5D might be good. It also has a full size sensor. But keep in mind its also three times more expensive. So the question I would ask is will the photos be 3 times better. In my opinion, 90% of the time, a independent viewer will not be able to tell the difference between photos shot between the two cameras. So for the difference in price, think how many good lens you could buy. Of course the 1.6 crop factor may be the major factor, so that has to be rolled into the equation also.
Canon 20D shot of Bridgette
Cheers,
rfs