1-Decca, Royal-Blue Columbia, Blue Victors, Bluebird, Philharmonic, and Brunswick are probably the best sounding shellac 78 records in my collection. Even on my mediocre turntable and without much processing, they're very quiet and very clear. Pretty much all of these are electrics, with a couple re-issues here and there.
2-Batwing/Scroll Victor, Blue/Gold or Red Columbia, HMV, and Vox records are fair-to-middlin' in terms of quality. Some are pretty noisy, others aren't, but they tend to clean up nicely once they're ran through filters and re-EQ'd. This includes both acoustics, electrics, and reissued recordings.
3-RCA Victors, some scroll Victors, Flag Columbias, and various off-brand labels (Mercury, Majestic, etc.) tend to sound very noisy, sometimes to the point of barely unlistenable. Sometimes, they clean up OK, but other times.....

Right now, the records that are giving me the most trouble are a set of Red-Seal scroll Victors, mostly from 1923-1927 (late acoustic, early electric era). It's mostly Chopin/Liszt/Schubert piano music, so a lot of times the music's buried under surface noise. Interestingly, the early electrics (and there are 3 or 4 of 'em in there) don't sound much better than the acoustics in the set. The ones from the early '30s are almost breathtaking, but the early ones are really underwhelming sound-wise. Any reason why?
Anyways, how about you guys?