People, best engineered is not the same as best sounding audiophile recording. Record engineering is the creative aspect of making the recording. Sound quality is only part of the equation.
I'm not going to put a lot thought into my list because I don't have the time or patience. I'm sure I could come up with a better list if I really thought this out. These are all predictable and nothing is surprising here. But I think these are hard to argue against (well maybe #5 doesn't belong but WTF ;)
Having said all this, here goes:
1. Revolver - Beatles
2. Pet Sounds - Beach Boys
3. Abbey Road - Beatles
4. Dark Side of the Moon - Pink Floyd
5. Exile on Main St - Rolling Stones (this is a "curve ball" selection I'm throwing in just because this is the ultimate "anti-engineered" album ... it sounds so murky, it is absolutely wonderful!)