I had the same predicament a couple of moths ago, I have used both camera before, and the 10d is obviously a better camera. I ended up getting the 300d, because I am poor. Best But let me trade in my broken Olympus C5050 for the full purchase price, so I only had to pay $100! My plan was to get the 300d, and get a few lenses (which I still havent done yet) and then when canon makes an affordable full frame dslr, I will get it. That probably won't happen for a while. But by then I might have more money.