Northern Test Zone

Living North of the 60th parallel can pose many challenges for photographers, especial those who use digital at -40C or lower. I had the opportunity to use a 20D in those insane temperatures without a glitch. About 3 months ago I upgraded to the 30D from the 20D. The 20D did amazingly well, not only in the North but also in the humid Dominican Republic.
My experience with the 30D has been great. I did have a few freeze ups with the new 580 flash, but soon found out that making sure the flash was securely screwed down and making good contact, those problems soon disappeared.
The 30D is fast to start, fast to focus and very accurate. This camera is great for the starter to the pro. Once you get to know the workings, it's a breeze to operate. I do caution though that this is not a weather-sealed camera, so be careful in the rain & dust. The 30D is tightly put together camera, but that doesn't mean you can throw caution to the wind, as the electronic components are very sensitive & delicate (as I found out on my 20D).
I would have bought the 5D but for the price, I would prefer a weather sealed unit. For the price of the 30D you are getting a very reliable and very fast camera with good menu layouts, superb image quality and a number of creative options.
You won't be disappointed, but I sure hope Canon weather seals the 5D, as the 30D would make an excellent primary or back up body. One other thing... stick with the "L" series lenses... huge difference when using quality glass with a great camera like the 30D. And if you plan to go full frame... you can interchange glass from one full frame to cropped. 30D is one tough reliable camera.. you won't be disappointed.