Debbie, something to think about with Minolta - since they are no longer making cameras or lenses, eBay is going to probably be your only source for finding something for it. I used to shoot with a Minolta X-370 manual camera and I had a 35-70 and then I wanted wide angle, so I bought a 28mm prime (just 28mm, not a zoom) lens for it. You will get a bit better quality with a prime wide angle, plus it will be a bit cheaper.

Bob, I'm shooting the 70-200/4 white Canon lens. I have Canon's 1.4x converter and I LOVE it. I only lose one stop of light, so it becomes a 5.6 lens, so your 2.8 would become an F4 lens. I have suffered no loss of quality, and it becomes the equivalent of a 448mm with the 1.6x factor. Your lens would be a 5.6 lens with the 2x converter, and though your images would look ok, they will start to suffer a bit of quality loss with the 2x converter. The converter for me was a cheap alternative to not investing to a longer focal length and takes up far less room in the camera bag than a 300mm lens does. I'd be more than happy to post some sample shots if you want to see some. What lenses do you have now for the 20D? My main landscape/lighthouse lens is Canon's 17-40/4 - one of their cheaper "L" lenses, at a whopping $579, but the quality has been nothing next to outstanding. I get the focal length of 27mm for wide angle and if I need to get 40-70mm focal length, I zoom with my feet.