According to the latest ratings by Consumer Reports, here are the vacs that rated only "fair" in noise level (all the rest were quieter):
Noisiest Bagged Uprights -
The top-rated Hoover Self Propelled Windtunnel Anniversary
The similar Hoover Turbopower version of the above
Riccar Supralite and Simplicity Freedom
Riccar Brilliance and Simplicity Synchrony
Oreck Edge
Dirt Devil Featherlite
Aerus Freshera
Cirrus Performance
Bottom rated Koblenz U610 (Sanitaire copy)
Noisiest Bagless Uprights:
Bissel Powerclean and HealthyHome
Germ Guardian
Eureka Lightforce 300
Noisiest Bagged Canister:
Metropolitan Professionals
Noisiest Bagless Canisters:
Dirt Devil Vision
Dyson DC22 Turbinehead