I might go ahead and make the jump to some FD / FL glass...
Well, if you do, the FL 55mm is something special. The focal length is very usable -- 88mm equivalent on my 7D. I haven't removed it from the camera since I got it!
The lens renders light a little differently than anything else I have used. It's a little warmer, but not distractingly so; it's very subtle. It doesn't flare too easily but when it does you get this great diffraction that can be really beautiful. The quality of the bokeh is similar -- it's creamy wide open but it has this viscocity to it -- and depending on the light source and aperture you can get a lot of different character from the out of focus highlights.
Shooting an f/1.2 is a real pleasure. Although it can be hard to nail the focus occassionally when wide open, I can shoot most anything, even handheld at night, with a quick shutter and low ISO. The lens is a great size and feels so much nicer and more significant than an EF lens. The focus ring is the smoothest of all my lenses.
Here's a couple more shots from a wedding this weekend. These are straight out of the camera -- no flash or special lighting and no post processing.