Most of us will get the Artic F12 but Corsair, BitFenix, Noiseblockers, Silent wings are a few that have very good quiet fans
Sidepanel fans will be much louder than the ones mounted on the actual frame of a chassis because the panel is not as solid in comparison so vibrations from fans mounted on them will be noisy, that is why I myself never have any fans mounted at the side panels even though there are mounting holes for them

and CM xtraflo have a few models with variable speeds so don't expect them to be quiet when they're at full speed, the 19DBA rating may have been over exaggerated like their sickleflow previously as well