I have the FD to EOS adapter from Adorama. The adapter has a glass element inside which is needed in order to focus to infinity. The element also acts as a weak 1.2x (approx) teleconverter and causes 1-stop of light loss. I've used an old FD 50mm 1.4 from a hand-me-down AE-1 and honestly, the results have not been great, probably because of the extra element, because pics that I take with the AE-1 and the 50mm 1.4 are not bad (but nowhere close to 30D and EF 50mm 1.4).
I've also tried the lens after removing the glass elements (2 pieces) from the adapter. Not only is the lens unable to achieve inifinity focus, it's practically useless since it acts like a lens with an extension tube on it. It's only able to focus on a very small range of distances.
From what I understand now, there is no way to get an element-less adapter and infinity focus together because the FD lens would need to mounted inside the EOS body, but then the mirror wouldn't be able to flip up (unless you do some serious surgery to your lens mount)
It's a bit ironic that "almost" every other non-Canon lens can be adapted well to EOS bodies but their own FD just doesn't work. I got 2 hand-me-down Leica R lenses that work very well on my 30D with a focus-confirm adapter that I picked up on fleaBay. I'm also considering picking up 1 or 2 Contax Zeiss lenses as well.
Try the Alternative Forum if you're interested in adapting non-EOS lenses to EOS bodies. I've learned so much from the veterans there.