Interesting - thought it was just me. I think the PW engined 777 is significantly quieter than the GE and Rolls powered equivalents and the Rolls is marginally quieter than the GE.
The 747 (except in first or upstairs) is showing its age and very noisy.
The A330 / 340 (I would suggest) is much quieter than either the 777 or 747, though the old ones seem noisier than the new.
I am told the A380 is astonishingly quiet.
This is based on flights in all classes - it is always noisier at the back.