Miele or sebo
I would go with a Miele or a Sebo, those are probably the two best brands available. I would avoid Riccar, I have a Riccar Prima canister, it's nice, I love it, but they have since moved all production to China and their quality has really gone down. Miele and Sebo are both very good though I think Sebo is slightly better quality and the parts are cheaper if it needs to be repaired.
I also have a Rainbow E2 black, they are ok but overpriced. Another canister you might consider is the Aerus classic, very much like the older Electrolux models, Perfect Products also makes a canister with a design similar to the old Electrolux.
Mike