I'd definitely get the ED80 and 40D/450D. The only downfall of the ED80 is that you'll want more focal length for "in your face" images of galaxies like NGC5128 or 4945 or M83 etc.
An ED100 will get you a little way there, but really you'll want to go to an 8" or 10" newt or (cough) SCT (gasp did I just say that!
) for the longer focal length.
Just be aware that the longer the focal length, the more challenges you face - in terms of accuracy in guiding and focusing. And with an SCT of course you've got the slow focal ratio as well meaning you double your exposure times.
I use an ED80 with 350D now, and it's great for widefield views - fit the entire Orion's sword in the FOV. But my next DSO imaging scope will be an 8" or 10" newt or fast SN. The ED80 will always come in handy for widefield images like Orion, Eta, etc.