You're all missing the most important thing:
It's all about how you hold your mouth.
On a serious note, I do think that if you are talking about instrumentals, then a
large part of "that sound" comes from the quality of instruments, excessive talent of the musicians, and quality of the actual arrangement. This is from the viewpoint of someone who hasn't even started the learning curve of recording yet... but is looking and listening as a musician. When I hear a great instrumental mix (even if it does have vocals), I immediately notice the raw talent of the musicians. It's obvious.
Then, on the other hand, there are some albums I hear that sound like a lot of money was dumped into making mediocre musicians sound good... and that is obvious as well. It's a bit difficult to explain, but it's like at the same time you think "wow, that recording sounds great" and "wow, those musicians aren't that hot." In my personal opinion, "great mixes" of the first type (great musical talent, good instruments, good arrangements) sound better, and to me
are better, than "great mixes" that sound good only in so far as you can tell that the "quality" of the recording process is good.
I don't feel like I'm making my point very clear.
Here's an example: I have many many different recordings of Rachmaninoff's piano concertos (me being a fan of his music). Two immediately come to mind, both the third concerto. One was recorded in the past few years, and was done with a studio orchestra for the purpose of producing a collection of Rachmaninoff's work. The piano was a Steinway I believe, the studio musicians (including pianist) were very good, and the overall performance was certainly competent (kinda like me calling a Ferrari a decent car

). The "quality of recording" was fantastic... the piano sound is great, balance between piano and orchestra (and different instruments) was spot on, and the overall sound is very "clean" (for lack of a better word). The second recording was done in 1969. It was a live recording. The orchestra sounds too distant in the mix, and the piano seems to have a bit too much room ambience in it. There is a low level hiss that was never eleminated from the recording, and both high and low frequencies have a very noticeabe falloff.
BUT, the orchestra performance was a notch above outstanding. And, the piano performance was nothing short of magical... a once in a lifetime performance that was lucky to have been captured on tape at all. Every note in 45 minutes of playing was beyond perfect.
You want to guess which one sounds better? Despite the obvious quality difference in the recording chain, the '69 recording simply sings, completely by virtue of the performance. Now, that may not be the case if it was captured on some old woman's cassette recorder.